Book space in a file, create I/O buffers, to fill them, (un)compress them.

The TKey class includes functions to book space in a file, to create I/O buffers, to fill these buffers, to compress/uncompress data buffers. Before saving (making persistent) an object in a file, a key must be created. The key structure contains all the information to uniquely identify a persistent object in a file.

Data Member	Explanation
fNbytes	Number of bytes for the compressed object and key.
fObjlen	Length of uncompressed object.
fDatime	Date/Time when the object was written.
fKeylen	Number of bytes for the key structure.
fCycle	Cycle number of the object.
fSeekKey	Address of the object on file (points to fNbytes). This is a redundant information used to cross-check the data base integrity.
fSeekPdir	Pointer to the directory supporting this object.
fClassName	Object class name.
fName	Name of the object.
fTitle	Title of the object.

In the 16 highest bits of fSeekPdir is encoded a pid offset. This offset is to be added to the pid index stored in the TRef object and the referenced TObject.

The TKey class is used by ROOT to:

Write an object in the current directory
Write a new ntuple buffer

The structure of a file is shown in TFile::TFile. The structure of a directory is shown in TDirectoryFile::TDirectoryFile. The TKey class is used by the TBasket class. See also TTree.

Definition at line 30 of file TKey.h.

Public Member Functions
	TKey ()

	TKey (TDirectory *motherDir)
	TKey default constructor. More...

	TKey (TDirectory *motherDir, const TKey &orig, UShort_t pidOffset)
	Copy a TKey from its original directory to the new 'motherDir'. More...

	TKey (const char name, const char title, const TClass cl, Int_t nbytes, TDirectory motherDir)
	Create a TKey object with the specified name, title for the given class. More...

	TKey (const TString &name, const TString &title, const TClass cl, Int_t nbytes, TDirectory motherDir)
	Create a TKey object with the specified name, title for the given class. More...

	TKey (const TObject obj, const char name, Int_t bufsize, TDirectory *motherDir)
	Create a TKey object for a TObject* and fill output buffer. More...

	TKey (const void obj, const TClass cl, const char name, Int_t bufsize, TDirectory motherDir)
	Create a TKey object for any object obj of class cl d and fill output buffer. More...

	TKey (Long64_t pointer, Int_t nbytes, TDirectory *motherDir=0)
	Create a TKey object to read keys. More...

virtual	~TKey ()
	TKey default destructor. More...

virtual void	Browse (TBrowser *b)
	Read object from disk and call its Browse() method. More...

virtual void	Delete (Option_t *option="")
	Delete an object from the file. More...

virtual void	DeleteBuffer ()
	Delete key buffer(s). More...

virtual void	FillBuffer (char *&buffer)
	Encode key header into output buffer. More...

virtual const char *	GetClassName () const

virtual const char *	GetIconName () const
	Title can keep 32x32 xpm thumbnail/icon of the parent object. More...

virtual const char *	GetTitle () const
	Returns title (title can contain 32x32 xpm thumbnail/icon). More...

virtual char *	GetBuffer () const

TBuffer *	GetBufferRef () const

Short_t	GetCycle () const
	Return cycle number associated to this key. More...

const TDatime &	GetDatime () const

TFile *	GetFile () const
	Returns file to which key belong. More...

Short_t	GetKeep () const
	Returns the "KEEP" status. More...

Int_t	GetKeylen () const

TDirectory *	GetMotherDir () const

Int_t	GetNbytes () const

Int_t	GetObjlen () const

Int_t	GetVersion () const

virtual Long64_t	GetSeekKey () const

virtual Long64_t	GetSeekPdir () const

virtual ULong_t	Hash () const
	This Hash function should redefine the default from TNamed. More...

virtual void	IncrementPidOffset (UShort_t offset)
	Increment fPidOffset by 'offset'. More...

Bool_t	IsFolder () const
	Check if object referenced by the key is a folder. More...

virtual void	Keep ()
	Set the "KEEP" status. More...

virtual void	ls (Option_t *option="") const
	List Key contents. More...

virtual void	Print (Option_t *option="") const
	Print key contents. More...

virtual Int_t	Read (TObject *obj)
	To read an object from the file. More...

virtual TObject *	ReadObj ()
	To read a TObject* from the file. More...

virtual TObject *	ReadObjWithBuffer (char *bufferRead)
	To read a TObject* from bufferRead. More...

virtual void *	ReadObjectAny (const TClass *expectedClass)
	To read an object (non deriving from TObject) from the file. More...

virtual void	ReadBuffer (char *&buffer)
	Decode input buffer. More...

void	ReadKeyBuffer (char *&buffer)
	Decode input buffer. More...

virtual Bool_t	ReadFile ()
	Read the key structure from the file. More...

virtual void	SetBuffer ()

virtual void	SetParent (const TObject *parent)
	Set parent in key buffer. More...

void	SetMotherDir (TDirectory *dir)

virtual Int_t	Sizeof () const
	Return the size in bytes of the key header structure. More...

virtual Int_t	WriteFile (Int_t cycle=1, TFile *f=0)
	Write the encoded object supported by this key. More...

	ClassDef (TKey, 4)

Public Member Functions inherited from TNamed
	TNamed ()

	TNamed (const char name, const char title)

	TNamed (const TString &name, const TString &title)

	TNamed (const TNamed &named)

TNamed &	operator= (const TNamed &rhs)
	TNamed assignment operator. More...

virtual	~TNamed ()

virtual void	Clear (Option_t *option="")
	Set name and title to empty strings (""). More...

virtual TObject *	Clone (const char *newname="") const
	Make a clone of an object using the Streamer facility. More...

virtual Int_t	Compare (const TObject *obj) const
	Compare two TNamed objects. More...

virtual void	Copy (TObject &named) const
	Copy this to obj. More...

virtual const char *	GetName () const
	Returns name of object. More...

virtual Bool_t	IsSortable () const

virtual void	SetName (const char *name)
	Change (i.e. More...

virtual void	SetNameTitle (const char name, const char title)
	Change (i.e. set) all the TNamed parameters (name and title). More...

virtual void	SetTitle (const char *title="")
	Change (i.e. set) the title of the TNamed. More...

Public Member Functions inherited from TObject
	TObject ()

	TObject (const TObject &object)
	TObject copy ctor. More...

TObject &	operator= (const TObject &rhs)
	TObject assignment operator. More...

virtual	~TObject ()
	TObject destructor. More...

virtual void	AppendPad (Option_t *option="")
	Append graphics object to current pad. More...

virtual const char *	ClassName () const
	Returns name of class to which the object belongs. More...

virtual Int_t	DistancetoPrimitive (Int_t px, Int_t py)
	Computes distance from point (px,py) to the object. More...

virtual void	Draw (Option_t *option="")
	Default Draw method for all objects. More...

virtual void	DrawClass () const
	Draw class inheritance tree of the class to which this object belongs. More...

virtual TObject *	DrawClone (Option_t *option="") const
	Draw a clone of this object in the current pad. More...

virtual void	Dump () const
	Dump contents of object on stdout. More...

virtual void	Execute (const char method, const char params, Int_t *error=0)
	Execute method on this object with the given parameter string, e.g. More...

virtual void	Execute (TMethod method, TObjArray params, Int_t *error=0)
	Execute method on this object with parameters stored in the TObjArray. More...

virtual void	ExecuteEvent (Int_t event, Int_t px, Int_t py)
	Execute action corresponding to an event at (px,py). More...

virtual TObject *	FindObject (const char *name) const
	Must be redefined in derived classes. More...

virtual TObject *	FindObject (const TObject *obj) const
	Must be redefined in derived classes. More...

virtual Option_t *	GetDrawOption () const
	Get option used by the graphics system to draw this object. More...

virtual UInt_t	GetUniqueID () const
	Return the unique object id. More...

virtual Option_t *	GetOption () const

virtual char *	GetObjectInfo (Int_t px, Int_t py) const
	Returns string containing info about the object at position (px,py). More...

virtual Bool_t	HandleTimer (TTimer *timer)
	Execute action in response of a timer timing out. More...

virtual Bool_t	InheritsFrom (const char *classname) const
	Returns kTRUE if object inherits from class "classname". More...

virtual Bool_t	InheritsFrom (const TClass *cl) const
	Returns kTRUE if object inherits from TClass cl. More...

virtual void	Inspect () const
	Dump contents of this object in a graphics canvas. More...

virtual Bool_t	IsEqual (const TObject *obj) const
	Default equal comparison (objects are equal if they have the same address in memory). More...

Bool_t	IsOnHeap () const

Bool_t	IsZombie () const

virtual Bool_t	Notify ()
	This method must be overridden to handle object notification. More...

virtual void	Paint (Option_t *option="")
	This method must be overridden if a class wants to paint itself. More...

virtual void	Pop ()
	Pop on object drawn in a pad to the top of the display list. More...

virtual void	RecursiveRemove (TObject *obj)
	Recursively remove this object from a list. More...

virtual void	SaveAs (const char filename="", Option_t option="") const
	Save this object in the file specified by filename. More...

virtual void	SavePrimitive (std::ostream &out, Option_t *option="")
	Save a primitive as a C++ statement(s) on output stream "out". More...

virtual void	SetDrawOption (Option_t *option="")
	Set drawing option for object. More...

virtual void	SetUniqueID (UInt_t uid)
	Set the unique object id. More...

virtual void	UseCurrentStyle ()
	Set current style settings in this object This function is called when either TCanvas::UseCurrentStyle or TROOT::ForceStyle have been invoked. More...

virtual Int_t	Write (const char *name=0, Int_t option=0, Int_t bufsize=0)
	Write this object to the current directory. More...

virtual Int_t	Write (const char *name=0, Int_t option=0, Int_t bufsize=0) const
	Write this object to the current directory. More...

void *	operator new (size_t sz)

void *	operator new[] (size_t sz)

void *	operator new (size_t sz, void *vp)

void *	operator new[] (size_t sz, void *vp)

void	operator delete (void *ptr)
	Operator delete. More...

void	operator delete[] (void *ptr)
	Operator delete []. More...

void	SetBit (UInt_t f, Bool_t set)
	Set or unset the user status bits as specified in f. More...

void	SetBit (UInt_t f)

void	ResetBit (UInt_t f)

Bool_t	TestBit (UInt_t f) const

Int_t	TestBits (UInt_t f) const

void	InvertBit (UInt_t f)

virtual void	Info (const char method, const char msgfmt,...) const
	Issue info message. More...

virtual void	Warning (const char method, const char msgfmt,...) const
	Issue warning message. More...

virtual void	Error (const char method, const char msgfmt,...) const
	Issue error message. More...

virtual void	SysError (const char method, const char msgfmt,...) const
	Issue system error message. More...

virtual void	Fatal (const char method, const char msgfmt,...) const
	Issue fatal error message. More...

void	AbstractMethod (const char *method) const
	Use this method to implement an "abstract" method that you don't want to leave purely abstract. More...

void	MayNotUse (const char *method) const
	Use this method to signal that a method (defined in a base class) may not be called in a derived class (in principle against good design since a child class should not provide less functionality than its parent, however, sometimes it is necessary). More...

void	Obsolete (const char method, const char asOfVers, const char *removedFromVers) const
	Use this method to declare a method obsolete. More...

Protected Member Functions
virtual Int_t	Read (const char *name)
	Read contents of object with specified name from the current directory. More...

virtual void	Create (Int_t nbytes, TFile *f=0)
	Create a TKey object of specified size. More...

void	Build (TDirectory motherDir, const char classname, Long64_t filepos)
	Method used in all TKey constructor to initialize basic data fields. More...

virtual void	Reset ()
	Reset the key as it had not been 'filled' yet. More...

virtual Int_t	WriteFileKeepBuffer (TFile *f=0)
	Write the encoded object supported by this key. More...

Protected Member Functions inherited from TObject
void	MakeZombie ()

virtual void	DoError (int level, const char location, const char fmt, va_list va) const
	Interface to ErrorHandler (protected). More...

Protected Attributes
Int_t	fVersion
	Key version identifier. More...

Int_t	fNbytes
	Number of bytes for the object on file. More...

Int_t	fObjlen
	Length of uncompressed object in bytes. More...

TDatime	fDatime
	Date/Time of insertion in file. More...

Short_t	fKeylen
	Number of bytes for the key itself. More...

Short_t	fCycle
	Cycle number. More...

Long64_t	fSeekKey
	Location of object on file. More...

Long64_t	fSeekPdir
	Location of parent directory on file. More...

TString	fClassName
	Object Class name. More...

Int_t	fLeft
	Number of bytes left in current segment. More...

char *	fBuffer
	Object buffer. More...

TBuffer *	fBufferRef
	Pointer to the TBuffer object. More...

UShort_t	fPidOffset
	!Offset to be added to the pid index in this key/buffer. This is actually saved in the high bits of fSeekPdir More...

TDirectory *	fMotherDir
	!pointer to mother directory More...

Protected Attributes inherited from TNamed
TString	fName

TString	fTitle

Private Types
enum	EStatusBits { kIsDirectoryFile = BIT(14) }

Private Member Functions
	TKey (const TKey &)

TKey &	operator= (const TKey &)

Additional Inherited Members
Public Types inherited from TObject
enum	EStatusBits { kCanDelete = BIT(0), kMustCleanup = BIT(3), kObjInCanvas = BIT(3), kIsReferenced = BIT(4), kHasUUID = BIT(5), kCannotPick = BIT(6), kNoContextMenu = BIT(8), kInvalidObject = BIT(13) }

enum	{ kIsOnHeap = 0x01000000, kNotDeleted = 0x02000000, kZombie = 0x04000000, kBitMask = 0x00ffffff }

enum	{ kSingleKey = BIT(0), kOverwrite = BIT(1), kWriteDelete = BIT(2) }

Static Public Member Functions inherited from TObject
static Long_t	GetDtorOnly ()
	Return destructor only flag. More...

static void	SetDtorOnly (void *obj)
	Set destructor only flag. More...

static Bool_t	GetObjectStat ()
	Get status of object stat flag. More...

static void	SetObjectStat (Bool_t stat)
	Turn on/off tracking of objects in the TObjectTable. More...

#include <TKey.h>

Inheritance diagram for TKey:

[legend]

Member Enumeration Documentation

enum TKey::EStatusBits

private

Enumerator
kIsDirectoryFile

Definition at line 33 of file TKey.h.

Constructor & Destructor Documentation

TKey::TKey ( const TKey & )

private

TKey::TKey ( )

TKey::TKey ( TDirectory * motherDir )

TKey default constructor.

Definition at line 104 of file TKey.cxx.

TKey::TKey	(	TDirectory *	motherDir,
		const TKey &	orig,
		UShort_t	pidOffset
	)

Copy a TKey from its original directory to the new 'motherDir'.

Definition at line 116 of file TKey.cxx.

TKey::TKey	(	const char *	name,
		const char *	title,
		const TClass *	cl,
		Int_t	nbytes,
		TDirectory *	motherDir
	)

Create a TKey object with the specified name, title for the given class.

WARNING: in name avoid special characters like '^','$','.' that are used by the regular expression parser (see TRegexp).

Definition at line 196 of file TKey.cxx.

TKey::TKey	(	const TString &	name,
		const TString &	title,
		const TClass *	cl,
		Int_t	nbytes,
		TDirectory *	motherDir
	)

Create a TKey object with the specified name, title for the given class.

WARNING: in name avoid special characters like '^','$','.' that are used by the regular expression parser (see TRegexp).

Definition at line 212 of file TKey.cxx.

TKey::TKey	(	const TObject *	obj,
		const char *	name,
		Int_t	bufsize,
		TDirectory *	motherDir
	)

Create a TKey object for a TObject* and fill output buffer.

WARNING: in name avoid special characters like '^','$','.' that are used by the regular expression parser (see TRegexp).

Definition at line 228 of file TKey.cxx.

TKey::TKey	(	const void *	obj,
		const TClass *	cl,
		const char *	name,
		Int_t	bufsize,
		TDirectory *	motherDir
	)

Create a TKey object for any object obj of class cl d and fill output buffer.

WARNING: in name avoid special characters like '^','$','.' that are used by the regular expression parser (see TRegexp).

Definition at line 301 of file TKey.cxx.

TKey::TKey	(	Long64_t	pointer,
		Int_t	nbytes,
		TDirectory *	motherDir = `0`
	)

Create a TKey object to read keys.

Constructor called by TDirectoryFile::ReadKeys and by TFile::TFile. A TKey object is created to read the keys structure itself.

Definition at line 180 of file TKey.cxx.

TKey::~TKey ( )

virtual

TKey default destructor.

Definition at line 517 of file TKey.cxx.

Member Function Documentation

void TKey::Browse ( TBrowser * b )

virtual

Read object from disk and call its Browse() method.

If object with same name already exist in memory delete it (like TDirectoryFile::Get() is doing), except when the key references a folder in which case we don't want to re-read the folder object since it might contain new objects not yet saved.

Reimplemented from TObject.

Definition at line 426 of file TKey.cxx.

void TKey::Build	(	TDirectory *	motherDir,
		const char *	classname,
		Long64_t	filepos
	)

protected

Method used in all TKey constructor to initialize basic data fields.

The member filepos is used to calculate correct version number of key if filepos==-1, end of file position is used.

Definition at line 391 of file TKey.cxx.

Referenced by TKey().

TKey::ClassDef	(	TKey	,
		4
	)

void TKey::Create	(	Int_t	nbytes,
		TFile *	externFile = `0`
	)

protectedvirtual

Create a TKey object of specified size.

If externFile!=0, key will be allocated in specified file, otherwise file of mother directory will be used.

Definition at line 458 of file TKey.cxx.

Referenced by TBasket::CopyTo(), TKey(), and TBasket::WriteBuffer().

void TKey::Delete ( Option_t * option = "" )

virtual

Delete an object from the file.

Note: the key is not deleted. You still have to call "delete key". This is different from the behaviour of TObject::Delete()!

Reimplemented from TObject.

Reimplemented in TKeySQL, and TKeyXML.

Definition at line 531 of file TKey.cxx.

Referenced by TTree::AutoSave(), TDirectoryFile::Delete(), TTree::Delete(), TDirectoryFile::Purge(), R__MigrateKey(), TDirectoryFile::WriteObjectAny(), and TDirectoryFile::WriteTObject().

void TKey::DeleteBuffer ( )

virtual

Delete key buffer(s).

Reimplemented in TKeySQL, and TKeyXML.

Definition at line 543 of file TKey.cxx.

Referenced by WriteFile(), and ~TKey().

void TKey::FillBuffer ( char *& buffer )

virtual

Encode key header into output buffer.

Reimplemented from TNamed.

Reimplemented in TKeySQL, and TKeyXML.

Definition at line 585 of file TKey.cxx.

Referenced by WriteFile(), and TDirectoryFile::WriteKeys().

virtual char* TKey::GetBuffer ( ) const

inlinevirtual

Reimplemented in TKeySQL, and TKeyXML.

Definition at line 80 of file TKey.h.

Referenced by TDirectoryFile::Init(), TFile::Init(), TFile::ReadFree(), TDirectoryFile::ReadKeys(), TFile::WriteFree(), and TDirectoryFile::WriteKeys().

TBuffer* TKey::GetBufferRef ( ) const

inline

Definition at line 81 of file TKey.h.

Referenced by TTreeSQL::CheckBasket(), TBranch::Fill(), TBranch::FlushOneBasket(), TBranch::GetEntry(), TBranch::GetEntryExport(), and TBasket::MoveEntries().

virtual const char* TKey::GetClassName ( ) const

inlinevirtual

Short_t TKey::GetCycle ( ) const

Return cycle number associated to this key.

Definition at line 561 of file TKey.cxx.

Referenced by TDirectoryFile::AppendKey(), TDirectoryFile::Browse(), TDirectoryFile::Delete(), TDirectoryFile::FindKeyAny(), TDirectoryFile::FindObjectAny(), TDirectoryFile::Get(), TDirectoryFile::GetKey(), TDirectoryFile::GetObjectChecked(), TKeySQL::IsKeyModified(), TRootBrowserLite::ListTreeHighlight(), ls(), Print(), TRootBrowserLite::ProcessMessage(), TFileIter::PurgeKeys(), TRootSniffer::ScanCollection(), TSQLFile::UpdateKeyData(), TMVA::variables(), and TSQLFile::WriteKeyData().

const TDatime& TKey::GetDatime ( ) const

inline

Definition at line 83 of file TKey.h.

Referenced by TKeySQL::IsKeyModified(), TSQLFile::UpdateKeyData(), and TSQLFile::WriteKeyData().

TFile * TKey::GetFile ( ) const

Returns file to which key belong.

Definition at line 569 of file TKey.cxx.

Referenced by Build(), Create(), TKeySQL::Delete(), Delete(), Read(), ReadFile(), TKeySQL::ReadKeyObject(), ReadObj(), ReadObjectAny(), ReadObjWithBuffer(), TKeyXML::StoreKeyAttributes(), TKeySQL::StoreKeyObject(), TKeyXML::StoreObject(), TKey(), TKeyXML::UpdateObject(), WriteFile(), WriteFileKeepBuffer(), TKeyXML::XMLEngine(), and TKeyXML::XmlReadAny().

const char * TKey::GetIconName ( ) const

virtual

Title can keep 32x32 xpm thumbnail/icon of the parent object.

Reimplemented from TObject.

Definition at line 1514 of file TKey.cxx.

Short_t TKey::GetKeep ( ) const

Returns the "KEEP" status.

Definition at line 577 of file TKey.cxx.

Referenced by TDirectoryFile::Purge().

Int_t TKey::GetKeylen ( ) const

inline

Definition at line 86 of file TKey.h.

Referenced by TBranch::AddBasket(), TBranch::GetEntry(), TBranch::GetEntryExport(), TDirectoryFile::Init(), TFile::Init(), TBasket::MoveEntries(), TTree::Print(), TBasket::Reset(), and TBranch::WriteBasket().

TDirectory* TKey::GetMotherDir ( ) const

inline

Definition at line 87 of file TKey.h.

Referenced by TKeySQL::GetDBDirId(), TKeySQL::StoreKeyObject(), and TKeyXML::TKeyXML().

Int_t TKey::GetNbytes ( ) const

inline

Definition at line 88 of file TKey.h.

Referenced by TBranch::AddBasket(), TTree::Delete(), TTree::Print(), TBranch::WriteBasket(), TFile::WriteFree(), TDirectoryFile::WriteKeys(), and TFile::WriteStreamerInfo().

Int_t TKey::GetObjlen ( ) const

inline

Definition at line 89 of file TKey.h.

Referenced by TBranch::AddBasket(), R__MigrateKey(), TBasket::Reset(), TBranch::WriteBasket(), TDirectoryFile::WriteObjectAny(), TFile::WriteStreamerInfo(), and TDirectoryFile::WriteTObject().

virtual Long64_t TKey::GetSeekKey ( ) const

inlinevirtual

Reimplemented in TKeySQL, and TKeyXML.

Definition at line 91 of file TKey.h.

Referenced by TBranch::AddBasket(), TBranch::GetBasket(), TDirectoryFile::Init(), TFile::Init(), TDirectoryFile::ReadKeys(), TBranch::WriteBasket(), TFile::WriteFree(), TDirectoryFile::WriteKeys(), TDirectoryFile::WriteObjectAny(), TFile::WriteStreamerInfo(), and TDirectoryFile::WriteTObject().

virtual Long64_t TKey::GetSeekPdir ( ) const

inlinevirtual

Reimplemented in TKeySQL, and TKeyXML.

Definition at line 92 of file TKey.h.

Referenced by TDirectoryFile::ReadKeys().

const char * TKey::GetTitle ( ) const

virtual

Returns title (title can contain 32x32 xpm thumbnail/icon).

Reimplemented from TNamed.

Definition at line 1522 of file TKey.cxx.

Referenced by Create(), TKeySQL::IsKeyModified(), ls(), Print(), TKeyXML::ReadObj(), TKeySQL::ReadObj(), ReadObj(), ReadObjectAny(), TKeyXML::ReadObjWithBuffer(), TKeySQL::ReadObjWithBuffer(), ReadObjWithBuffer(), TSQLFile::ReadSpecialObject(), TKeyXML::StoreKeyAttributes(), TSQLFile::UpdateKeyData(), WriteFile(), WriteFileKeepBuffer(), and TSQLFile::WriteKeyData().

Int_t TKey::GetVersion ( ) const

inline

Definition at line 90 of file TKey.h.

ULong_t TKey::Hash ( ) const

virtual

This Hash function should redefine the default from TNamed.

Reimplemented from TNamed.

Definition at line 624 of file TKey.cxx.

void TKey::IncrementPidOffset ( UShort_t offset )

virtual

Increment fPidOffset by 'offset'.

This offset is used when a key (or basket) is transfered from one file to the other. In this case the TRef and TObject might have stored a pid index (to retrieve TProcessIDs) which refered to their order on the original file, the fPidOffset is to be added to those values to correctly find the TProcessID. This fPidOffset needs to be increment if the key/basket is copied and need to be zero for new key/basket.

Definition at line 639 of file TKey.cxx.

Referenced by TTreeCloner::WriteBaskets().

Bool_t TKey::IsFolder ( ) const

virtual

Check if object referenced by the key is a folder.

Reimplemented from TObject.

Definition at line 653 of file TKey.cxx.

void TKey::Keep ( )

virtual

Set the "KEEP" status.

When the KEEP flag is set to 1 the object cannot be purged.

Reimplemented in TKeySQL, and TKeyXML.

Definition at line 674 of file TKey.cxx.

void TKey::ls ( Option_t * option = "" ) const

virtual

List Key contents.

Reimplemented from TNamed.

Definition at line 682 of file TKey.cxx.

Referenced by TDirectoryFile::ls().

TKey& TKey::operator= ( const TKey & )

private

void TKey::Print ( Option_t * option = "" ) const

virtual

Print key contents.

Reimplemented from TNamed.

Definition at line 691 of file TKey.cxx.

virtual Int_t TKey::Read ( const char * name )

inlineprotectedvirtual

Read contents of object with specified name from the current directory.

First the key with the given name is searched in the current directory, next the key buffer is deserialized into the object. The object must have been created before via the default constructor. See TObject::Write().

Reimplemented from TObject.

Reimplemented in TKeyXML, and TKeySQL.

Definition at line 55 of file TKey.h.

Referenced by TKeySQL::Read(), TKeyXML::Read(), and TDirectoryFile::ReadTObject().

Int_t TKey::Read ( TObject * obj )

virtual

To read an object from the file.

The object associated to this key is read from the file into memory. Before invoking this function, obj has been created via the default constructor.

Reimplemented in TKeySQL, and TKeyXML.

Definition at line 1143 of file TKey.cxx.

void TKey::ReadBuffer ( char *& buffer )

virtual

Decode input buffer.

In some situation will add key to gDirectory.

Reimplemented in TKeySQL, and TKeyXML.

Definition at line 1203 of file TKey.cxx.

Bool_t TKey::ReadFile ( )

virtual

Read the key structure from the file.

Reimplemented in TKeySQL, and TKeyXML.

Definition at line 1258 of file TKey.cxx.

Referenced by Read(), TFile::ReadFree(), TDirectoryFile::ReadKeys(), ReadObj(), ReadObjectAny(), and ReadObjWithBuffer().

void TKey::ReadKeyBuffer ( char *& buffer )

Decode input buffer.

Definition at line 1215 of file TKey.cxx.

Referenced by TFile::GetStreamerInfoList(), ReadBuffer(), TFile::ReadFree(), TDirectoryFile::ReadKeys(), and TFile::Recover().

TObject * TKey::ReadObj ( )

virtual

To read a TObject* from the file.

The object associated to this key is read from the file into memory Once the key structure is read (via Streamer) the class identifier of the object is known. Using the class identifier we find the TClass object for this class. A TClass object contains a full description (i.e. dictionary) of the associated class. In particular the TClass object can create a new object of the class type it describes. This new object now calls its Streamer function to rebuilt itself.

Use TKey::ReadObjectAny to read any object non-derived from TObject

Note

A C style cast can only be used in the case where the final class of this object derives from TObject as a first inheritance, otherwise one must use a dynamic_cast.

Example1: simplified case

class MyClass : public TObject, public AnotherClass then on return, one get away with using: MyClass obj = (MyClass)key->ReadObj();

Example2: Usual case (recommended unless performance is critical)

MyClass obj = dynamic_cast<MyClass>(key->ReadObj()); which support also the more complex inheritance like: class MyClass : public AnotherClass, public TObject

Of course, dynamic_cast<> can also be used in the example 1.

Reimplemented in TKeySQL, and TKeyXML.

Definition at line 727 of file TKey.cxx.

Referenced by TMVA::annconvergencetest(), TMVA::BDTControlPlots(), TMVA::BoostControlPlots(), Browse(), TMVA::compareanapp(), TMVA::CorrGui(), TMVA::draw_network(), TDirectoryFile::FindObjectAny(), TDirectoryFile::Get(), TDSetElement::GetEntries(), TVirtualPacketizer::GetEntries(), TDSet::GetEntries(), TMVA::likelihoodrefs(), TEventIterTree::Load(), TEntryListFromFile::LoadList(), TFileMerger::MergeRecursive(), TMVA::plot_efficiencies(), TEventIterObj::PreProcessEvent(), TEntryListFromFile::Print(), TMVA::probas(), TDirectoryFile::ReadAll(), TMVA::rulevisCorr(), TMVA::rulevisHists(), TRootSniffer::ScanCollection(), and TMVA::variables().

void * TKey::ReadObjectAny ( const TClass * expectedClass )

virtual

To read an object (non deriving from TObject) from the file.

If expectedClass is not null, we checked that that actual class of the object stored is suitable to be stored in a pointer pointing to an object of class 'expectedClass'. We also adjust the value of the returned address so that it is suitable to be cast (C-Style) a pointer pointing to an object of class 'expectedClass'.

So for example if the class Bottom inherits from Top and the object stored is of type Bottom you can safely do:

auto TopClass = TClass::GetClass("Top");
auto ptr = (Top*) key->ReadObjectAny( TopClass );
if (ptr==0) printError("the object stored in the key is not of the expected type\n");

The object associated to this key is read from the file into memory. Once the key structure is read (via Streamer) the class identifier of the object is known. Using the class identifier we find the TClass object for this class. A TClass object contains a full description (i.e. dictionary) of the associated class. In particular the TClass object can create a new object of the class type it describes. This new object now calls its Streamer function to rebuilt itself.

Reimplemented in TKeySQL, and TKeyXML.

Definition at line 1005 of file TKey.cxx.

Referenced by TDirectoryFile::GetObjectChecked(), ReadObj(), and ReadObjWithBuffer().

TObject * TKey::ReadObjWithBuffer ( char * bufferRead )

virtual

To read a TObject* from bufferRead.

This function is identical to TKey::ReadObj, but it reads directly from bufferRead instead of reading from a file. The object associated to this key is read from the buffer into memory Using the class identifier we find the TClass object for this class. A TClass object contains a full description (i.e. dictionary) of the associated class. In particular the TClass object can create a new object of the class type it describes. This new object now calls its Streamer function to rebuilt itself.

Note

This function is called only internally by ROOT classes. Although being public it is not supposed to be used outside ROOT. If used, you must make sure that the bufferRead is large enough to accomodate the object being read.

Reimplemented in TKeySQL, and TKeyXML.

Definition at line 869 of file TKey.cxx.

Referenced by TFile::GetStreamerInfoList().

void TKey::Reset ( void )

protectedvirtual

Reset the key as it had not been 'filled' yet.

Reimplemented in TBasket, and TBasketSQL.

Definition at line 1295 of file TKey.cxx.

Referenced by TBasket::Reset().

virtual void TKey::SetBuffer ( )

inlinevirtual

Reimplemented in TKeySQL, and TKeyXML.

Definition at line 106 of file TKey.h.

void TKey::SetMotherDir ( TDirectory * dir )

inline

Definition at line 108 of file TKey.h.

Referenced by TDirectoryFile::AppendKey().

void TKey::SetParent ( const TObject * parent )

virtual

Set parent in key buffer.

Definition at line 1287 of file TKey.cxx.

Referenced by TBranch::SetFile(), and TBranch::UpdateFile().

Int_t TKey::Sizeof ( ) const

virtual

Return the size in bytes of the key header structure.

An explaination about the nbytes (Int_t nbytes) variable used in the function. The size of fSeekKey and fSeekPdir is 8 instead of 4 if version is greater than 1000.