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TKey Class Reference

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:

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
 
TBufferGetBufferRef () const
 
Short_t GetCycle () const
 Return cycle number associated to this key. More...
 
const TDatimeGetDatime () const
 
TFileGetFile () const
 Returns file to which key belong. More...
 
Short_t GetKeep () const
 Returns the "KEEP" status. More...
 
Int_t GetKeylen () const
 
TDirectoryGetMotherDir () 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 TObjectReadObj ()
 To read a TObject* from the file. More...
 
virtual TObjectReadObjWithBuffer (char *bufferRead)
 To read a TObject* from bufferRead. More...
 
virtual voidReadObjectAny (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)
 
TNamedoperator= (const TNamed &rhs)
 TNamed assignment operator. More...
 
virtual ~TNamed ()
 
virtual void Clear (Option_t *option="")
 Set name and title to empty strings (""). More...
 
virtual TObjectClone (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...
 
TObjectoperator= (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 TObjectDrawClone (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 TObjectFindObject (const char *name) const
 Must be redefined in derived classes. More...
 
virtual TObjectFindObject (const TObject *obj) const
 Must be redefined in derived classes. More...
 
virtual Option_tGetDrawOption () 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_tGetOption () 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...
 
voidoperator new (size_t sz)
 
voidoperator new[] (size_t sz)
 
voidoperator new (size_t sz, void *vp)
 
voidoperator 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...
 
TBufferfBufferRef
 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...
 
TDirectoryfMotherDir
 !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 &)
 
TKeyoperator= (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  ,
 
)
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
TBuffer* TKey::GetBufferRef ( ) const
inline
virtual const char* TKey::GetClassName ( ) const
inlinevirtual
Short_t TKey::GetCycle ( ) const
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
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
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
Int_t TKey::GetObjlen ( ) const
inline
virtual Long64_t TKey::GetSeekKey ( ) const
inlinevirtual
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
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.

Component Sizeof
fNbytes 4
sizeof(Version_t) 2
fObjlen 4
fKeylen 2
fCycle 2
fSeekKey 4 or 8
fSeekPdir 4 or 8
TOTAL 22

Reimplemented from TNamed.

Definition at line 1329 of file TKey.cxx.

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

Int_t TKey::WriteFile ( Int_t  cycle = 1,
TFile f = 0 
)
virtual

Write the encoded object supported by this key.

The function returns the number of bytes committed to the file. If a write error occurs, the number of bytes returned is -1.

Reimplemented in TKeySQL, and TKeyXML.

Definition at line 1440 of file TKey.cxx.

Referenced by TDirectoryFile::Init(), TFile::Init(), R__MigrateKey(), TBasket::WriteBuffer(), TFile::WriteFree(), TDirectoryFile::WriteKeys(), TDirectoryFile::WriteObjectAny(), TFile::WriteStreamerInfo(), and TDirectoryFile::WriteTObject().

Int_t TKey::WriteFileKeepBuffer ( TFile f = 0)
protectedvirtual

Write the encoded object supported by this key.

The function returns the number of bytes committed to the file. If a write error occurs, the number of bytes returned is -1.

Definition at line 1481 of file TKey.cxx.

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

Member Data Documentation

char* TKey::fBuffer
protected
TBuffer* TKey::fBufferRef
protected
TString TKey::fClassName
protected
Short_t TKey::fCycle
protected
TDatime TKey::fDatime
protected
Short_t TKey::fKeylen
protected
Int_t TKey::fLeft
protected

Number of bytes left in current segment.

Definition at line 49 of file TKey.h.

Referenced by Build(), Create(), Reset(), TKey(), WriteFile(), and WriteFileKeepBuffer().

TDirectory* TKey::fMotherDir
protected
Int_t TKey::fNbytes
protected
Int_t TKey::fObjlen
protected
UShort_t TKey::fPidOffset
protected

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

Definition at line 52 of file TKey.h.

Referenced by Build(), FillBuffer(), IncrementPidOffset(), Read(), ReadKeyBuffer(), ReadObj(), ReadObjectAny(), ReadObjWithBuffer(), Reset(), and TKey().

Long64_t TKey::fSeekKey
protected

Location of object on file.

Definition at line 46 of file TKey.h.

Referenced by Build(), Create(), Delete(), FillBuffer(), GetSeekKey(), ReadFile(), ReadKeyBuffer(), Reset(), and TKey().

Long64_t TKey::fSeekPdir
protected

Location of parent directory on file.

Definition at line 47 of file TKey.h.

Referenced by Build(), Create(), FillBuffer(), GetSeekPdir(), ReadBuffer(), ReadKeyBuffer(), Reset(), and TKey().

Int_t TKey::fVersion
protected

Key version identifier.

Definition at line 40 of file TKey.h.

Referenced by Build(), FillBuffer(), GetVersion(), IncrementPidOffset(), Read(), ReadKeyBuffer(), Sizeof(), TBasket::TBasket(), and TKey().

Collaboration diagram for TKey:
[legend]

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