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Reference Guide
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TClonesArray Class Reference

An array of clone (identical) objects.

Memory for the objects stored in the array is allocated only once in the lifetime of the clones array. All objects must be of the same class. For the rest this class has the same properties as TObjArray.

To reduce the very large number of new and delete calls in large loops like this (O(100000) x O(10000) times new/delete):

TObjArray a(10000);
while (TEvent *ev = (TEvent *)next()) { // O(100000) events
for (int i = 0; i < ev->Ntracks; i++) { // O(10000) tracks
a[i] = new TTrack(x,y,z,...);
...
...
}
...
a.Delete();
}

One better uses a TClonesArray which reduces the number of new/delete calls to only O(10000):

TClonesArray a("TTrack", 10000);
while (TEvent *ev = (TEvent *)next()) { // O(100000) events
for (int i = 0; i < ev->Ntracks; i++) { // O(10000) tracks
new(a[i]) TTrack(x,y,z,...);
...
...
}
...
a.Delete(); // or a.Clear() or a.Clear("C")
}

To reduce the number of call to the constructor (especially useful if the user class requires memory allocation), the object can be added (and constructed when needed) using ConstructedAt which only calls the constructor once per slot.

TClonesArray a("TTrack", 10000);
while (TEvent *ev = (TEvent *)next()) { // O(100000) events
for (int i = 0; i < ev->Ntracks; i++) { // O(10000) tracks
TTrack *track = (TTrack*)a.ConstructedAt(i);
track->Set(x,y,z,....);
...
...
}
...
a.Clear(); // or a.Clear("C");
}

Note: the only supported way to add objects to a TClonesArray is via the new with placement method or the ConstructedAt method. The other Add() methods ofTObjArray and its base classes are not allowed.

Considering that a new/delete costs about 70 mus on a 300 MHz HP, O(10^9) new/deletes will save about 19 hours.

NOTE 1

C/C++ offers the possibility of allocating and deleting memory. Forgetting to delete allocated memory is a programming error called a "memory leak", i.e. the memory of your process grows and eventually your program crashes. Even if you always delete the allocated memory, the recovered space may not be efficiently reused. The process knows that there are portions of free memory, but when you allocate it again, a fresh piece of memory is grabbed. Your program is free from semantic errors, but the total memory of your process still grows, because your program's memory is full of "holes" which reduce the efficiency of memory access; this is called "memory fragmentation". Moreover new / delete are expensive operations in terms of CPU time.

Without entering into technical details, TClonesArray allows you to "reuse" the same portion of memory for new/delete avoiding memory fragmentation and memory growth and improving the performance by orders of magnitude. Every time the memory of the TClonesArray has to be reused, the Clear() method is used. To provide its benefits, each TClonesArray must be allocated once per process and disposed of (deleted) only when not needed any more.

So a job should see only one deletion for each TClonesArray, which should be Clear()ed during the job several times. Deleting a TClonesArray is a double waste. Not only you do not avoid memory fragmentation, but you worsen it because the TClonesArray itself is a rather heavy structure, and there is quite some code in the destructor, so you have more memory fragmentation and slower code.

NOTE 2

When investigating misuse of TClonesArray, please make sure of the following:

Definition at line 32 of file TClonesArray.h.

Public Types

enum  { kForgetBits = BIT(0), kNoSplit = BIT(1), kBypassStreamer = BIT(12) }
 Saved copies of pointers to objects. More...
 
- Public Types inherited from TObjArray
typedef TObjArrayIter Iterator_t
 
- Public Types inherited from TCollection
enum  { kInitCapacity = 16, kInitHashTableCapacity = 17 }
 
- Public Types inherited from TObject
enum  { kIsOnHeap = 0x01000000, kNotDeleted = 0x02000000, kZombie = 0x04000000, kBitMask = 0x00ffffff }
 
enum  { kSingleKey = BIT(0), kOverwrite = BIT(1), kWriteDelete = BIT(2) }
 
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)
}
 

Public Member Functions

 TClonesArray ()
 Default Constructor. More...
 
 TClonesArray (const char *classname, Int_t size=1000, Bool_t call_dtor=kFALSE)
 Create an array of clone objects of classname. More...
 
 TClonesArray (const TClass *cl, Int_t size=1000, Bool_t call_dtor=kFALSE)
 Create an array of clone objects of class cl. More...
 
 TClonesArray (const TClonesArray &tc)
 Copy ctor. More...
 
virtual ~TClonesArray ()
 Delete a clones array. More...
 
void AbsorbObjects (TClonesArray *tc)
 Directly move the object pointers from tc without cloning (copying). More...
 
void AbsorbObjects (TClonesArray *tc, Int_t idx1, Int_t idx2)
 Directly move the range of object pointers from tc without cloning (copying). More...
 
void AddAfter (const TObject *, TObject *)
 Add object in the slot after object after. More...
 
void AddAt (TObject *, Int_t)
 Add object at position ids. More...
 
void AddAtAndExpand (TObject *, Int_t)
 Add object at position idx. More...
 
Int_t AddAtFree (TObject *)
 Return the position of the new object. More...
 
void AddBefore (const TObject *, TObject *)
 Add object in the slot before object before. More...
 
void AddFirst (TObject *)
 Add object in the first slot of the array. More...
 
void AddLast (TObject *)
 Add object in the next empty slot in the array. More...
 
TObjectAddrAt (Int_t idx)
 
void BypassStreamer (Bool_t bypass=kTRUE)
 When the kBypassStreamer bit is set, the automatically generated Streamer can call directly TClass::WriteBuffer. More...
 
Bool_t CanBypassStreamer () const
 
virtual void Clear (Option_t *option="")
 Clear the clones array. More...
 
virtual void Compress ()
 Remove empty slots from array. More...
 
TObjectConstructedAt (Int_t idx)
 Get an object at index 'idx' that is guaranteed to have been constructed. More...
 
TObjectConstructedAt (Int_t idx, Option_t *clear_options)
 Get an object at index 'idx' that is guaranteed to have been constructed. More...
 
virtual void Delete (Option_t *option="")
 Clear the clones array. More...
 
virtual void Expand (Int_t newSize)
 Expand or shrink the array to newSize elements. More...
 
virtual void ExpandCreate (Int_t n)
 Expand or shrink the array to n elements and create the clone objects by calling their default ctor. More...
 
virtual void ExpandCreateFast (Int_t n)
 Expand or shrink the array to n elements and create the clone objects by calling their default ctor. More...
 
TClassGetClass () const
 
void MultiSort (Int_t nTCs, TClonesArray **tcs, Int_t upto=kMaxInt)
 Sort multiple TClonesArrays simultaneously with this array. More...
 
TObjectNew (Int_t idx)
 Create an object of type fClass with the default ctor at the specified index. More...
 
TClonesArrayoperator= (const TClonesArray &tc)
 Assignment operator. More...
 
TObject *& operator[] (Int_t idx)
 Return pointer to reserved area in which a new object of clones class can be constructed. More...
 
TObjectoperator[] (Int_t idx) const
 Return the object at position idx. Returns 0 if idx is out of bounds. More...
 
virtual TObjectRemove (TObject *obj)
 Remove object from array. More...
 
virtual TObjectRemoveAt (Int_t idx)
 Remove object at index idx. More...
 
virtual void RemoveRange (Int_t idx1, Int_t idx2)
 Remove objects from index idx1 to idx2 included. More...
 
void SetClass (const char *classname, Int_t size=1000)
 see TClonesArray::SetClass(const TClass*) More...
 
void SetClass (const TClass *cl, Int_t size=1000)
 Create an array of clone objects of class cl. More...
 
virtual void SetOwner (Bool_t enable=kTRUE)
 A TClonesArray is always the owner of the object it contains. More...
 
virtual void Sort (Int_t upto=kMaxInt)
 If objects in array are sortable (i.e. More...
 
- Public Member Functions inherited from TObjArray
 TObjArray (Int_t s=TCollection::kInitCapacity, Int_t lowerBound=0)
 Create an object array. More...
 
 TObjArray (const TObjArray &a)
 Create a copy of TObjArray a. Note, does not copy the kIsOwner flag. More...
 
virtual ~TObjArray ()
 Delete an array. More...
 
void Add (TObject *obj)
 
TObjectAfter (const TObject *obj) const
 Return the object after obj. Returns 0 if obj is last object. More...
 
TObjectAt (Int_t idx) const
 
TObjectBefore (const TObject *obj) const
 Return the object before obj. Returns 0 if obj is first object. More...
 
virtual Int_t BinarySearch (TObject *obj, Int_t upto=kMaxInt)
 Find object using a binary search. More...
 
virtual TObjectFindObject (const char *name) const
 Find an object in this collection using its name. More...
 
virtual TObjectFindObject (const TObject *obj) const
 Find an object in this collection using the object's IsEqual() member function. More...
 
TObjectFirst () const
 Return the object in the first slot. More...
 
Int_t GetEntries () const
 Return the number of objects in array (i.e. More...
 
Int_t GetEntriesFast () const
 
Int_t GetLast () const
 Return index of last object in array. More...
 
TObject ** GetObjectRef () const
 
TObject ** GetObjectRef (const TObject *obj) const
 Return address of pointer obj. If obj is 0 returns address of container. More...
 
Int_t IndexOf (const TObject *obj) const
 
Bool_t IsEmpty () const
 
TObjectLast () const
 Return the object in the last filled slot. Returns 0 if no entries. More...
 
Int_t LowerBound () const
 
TIteratorMakeIterator (Bool_t dir=kIterForward) const
 Returns an array iterator. More...
 
TObjArrayoperator= (const TObjArray &)
 Assignment operator. Note, unsets the kIsOwner flag. More...
 
virtual void Randomize (Int_t ntimes=1)
 Randomize objects inside the array, i.e. More...
 
virtual void RecursiveRemove (TObject *obj)
 Remove object from this collection and recursively remove the object from all other objects (and collections). More...
 
void SetLast (Int_t last)
 Set index of last object in array, effectively truncating the array. More...
 
TObjectUncheckedAt (Int_t i) const
 
- Public Member Functions inherited from TSeqCollection
virtual ~TSeqCollection ()
 
virtual Bool_t IsSorted () const
 
Int_t LastIndex () const
 
Long64_t Merge (TCollection *list)
 Merge this collection with all collections coming in the input list. More...
 
virtual void RemoveAfter (TObject *after)
 
virtual void RemoveBefore (TObject *before)
 
virtual void RemoveFirst ()
 
virtual void RemoveLast ()
 
void UnSort ()
 
- Public Member Functions inherited from TCollection
virtual ~TCollection ()
 
virtual void AddAll (const TCollection *col)
 Add all objects from collection col to this collection. More...
 
void AddVector (TObject *obj1,...)
 Add all arguments to the collection. More...
 
Bool_t AssertClass (TClass *cl) const
 Make sure all objects in this collection inherit from class cl. More...
 
TIter begin () const
 
void Browse (TBrowser *b)
 Browse this collection (called by TBrowser). More...
 
Int_t Capacity () const
 
virtual TObjectClone (const char *newname="") const
 Make a clone of an collection using the Streamer facility. More...
 
Int_t Compare (const TObject *obj) const
 Compare two TCollection objects. More...
 
Bool_t Contains (const char *name) const
 
Bool_t Contains (const TObject *obj) const
 
virtual void Draw (Option_t *option="")
 Draw all objects in this collection. More...
 
virtual void Dump () const
 Dump all objects in this collection. More...
 
TIter end () const
 
virtual const char * GetName () const
 Return name of this collection. More...
 
virtual Int_t GetSize () const
 
virtual Int_t GrowBy (Int_t delta) const
 Increase the collection's capacity by delta slots. More...
 
ULong_t Hash () const
 Return hash value for this object. More...
 
Bool_t IsArgNull (const char *where, const TObject *obj) const
 Returns true if object is a null pointer. More...
 
virtual Bool_t IsFolder () const
 Returns kTRUE in case object contains browsable objects (like containers or lists of other objects). More...
 
Bool_t IsOwner () const
 
Bool_t IsSortable () const
 
virtual void ls (Option_t *option="") const
 List (ls) all objects in this collection. More...
 
virtual TIteratorMakeReverseIterator () const
 
virtual Bool_t Notify ()
 'Notify' all objects in this collection. More...
 
TObjectoperator() (const char *name) const
 Find an object in this collection by name. More...
 
virtual void Paint (Option_t *option="")
 Paint all objects in this collection. More...
 
virtual void Print (Option_t *option="") const
 Default print for collections, calls Print(option, 1). More...
 
virtual void Print (Option_t *option, Int_t recurse) const
 Print the collection header and its elements. More...
 
virtual void Print (Option_t *option, const char *wildcard, Int_t recurse=1) const
 Print the collection header and its elements that match the wildcard. More...
 
virtual void Print (Option_t *option, TPRegexp &regexp, Int_t recurse=1) const
 Print the collection header and its elements that match the regexp. More...
 
virtual void RemoveAll (TCollection *col)
 Remove all objects in collection col from this collection. More...
 
void RemoveAll ()
 
void SetCurrentCollection ()
 Set this collection to be the globally accesible collection. More...
 
void SetName (const char *name)
 
virtual Int_t Write (const char *name=0, Int_t option=0, Int_t bufsize=0)
 Write all objects in this collection. More...
 
virtual Int_t Write (const char *name=0, Int_t option=0, Int_t bufsize=0) const
 Write all objects in this collection. More...
 
- Public Member Functions inherited from TObject
 TObject ()
 TObject constructor. More...
 
 TObject (const TObject &object)
 TObject copy ctor. More...
 
virtual ~TObject ()
 TObject destructor. 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...
 
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 void Copy (TObject &object) const
 Copy this to obj. More...
 
virtual Int_t DistancetoPrimitive (Int_t px, Int_t py)
 Computes distance from point (px,py) to the object. 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 selected pad for instance with: gROOT->SetSelectedPad(gPad). More...
 
virtual void Error (const char *method, const char *msgfmt,...) const
 Issue error message. 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 void Fatal (const char *method, const char *msgfmt,...) const
 Issue fatal error message. More...
 
virtual Option_tGetDrawOption () const
 Get option used by the graphics system to draw this object. More...
 
virtual const char * GetIconName () const
 Returns mime type name of object. More...
 
virtual char * GetObjectInfo (Int_t px, Int_t py) const
 Returns string containing info about the object at position (px,py). More...
 
virtual Option_tGetOption () const
 
virtual const char * GetTitle () const
 Returns title of object. More...
 
virtual UInt_t GetUniqueID () const
 Return the unique object id. More...
 
virtual Bool_t HandleTimer (TTimer *timer)
 Execute action in response of a timer timing out. More...
 
virtual void Info (const char *method, const char *msgfmt,...) const
 Issue info message. 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...
 
void InvertBit (UInt_t f)
 
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
 
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...
 
void operator delete (void *ptr)
 Operator delete. More...
 
void operator delete[] (void *ptr)
 Operator delete []. More...
 
voidoperator new (size_t sz)
 
voidoperator new (size_t sz, void *vp)
 
voidoperator new[] (size_t sz)
 
voidoperator new[] (size_t sz, void *vp)
 
TObjectoperator= (const TObject &rhs)
 TObject assignment operator. More...
 
virtual void Pop ()
 Pop on object drawn in a pad to the top of the display list. More...
 
virtual Int_t Read (const char *name)
 Read contents of object with specified name from the current directory. More...
 
void ResetBit (UInt_t f)
 
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...
 
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)
 
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 SysError (const char *method, const char *msgfmt,...) const
 Issue system error message. More...
 
Bool_t TestBit (UInt_t f) const
 
Int_t TestBits (UInt_t f) const
 
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 void Warning (const char *method, const char *msgfmt,...) const
 Issue warning message. More...
 

Protected Attributes

TClassfClass
 
TObjArrayfKeep
 Pointer to the class of the elements. More...
 
- Protected Attributes inherited from TObjArray
TObject ** fCont
 
Int_t fLast
 
Int_t fLowerBound
 Array contents. More...
 
- Protected Attributes inherited from TSeqCollection
Bool_t fSorted
 
- Protected Attributes inherited from TCollection
TString fName
 
Int_t fSize
 

Additional Inherited Members

- Static Public Member Functions inherited from TSeqCollection
static Int_t ObjCompare (TObject *a, TObject *b)
 Compare to objects in the collection. Use member Compare() of object a. More...
 
static void QSort (TObject **a, Int_t first, Int_t last)
 Sort array of TObject pointers using a quicksort algorithm. More...
 
static void QSort (TObject **a, TObject **b, Int_t first, Int_t last)
 
static void QSort (TObject **a, Int_t nBs, TObject ***b, Int_t first, Int_t last)
 Sort array a of TObject pointers using a quicksort algorithm. More...
 
- Static Public Member Functions inherited from TCollection
static void EmptyGarbageCollection ()
 Do the garbage collection. More...
 
static void GarbageCollect (TObject *obj)
 Add to the list of things to be cleaned up. More...
 
static TCollectionGetCurrentCollection ()
 Return the globally accessible collection. More...
 
static void StartGarbageCollection ()
 Set up for garbage collection. More...
 
- Static Public Member Functions inherited from TObject
static Long_t GetDtorOnly ()
 Return destructor only flag. More...
 
static Bool_t GetObjectStat ()
 Get status of object stat flag. More...
 
static void SetDtorOnly (void *obj)
 Set destructor only flag. More...
 
static void SetObjectStat (Bool_t stat)
 Turn on/off tracking of objects in the TObjectTable. More...
 
- Protected Types inherited from TCollection
enum  { kIsOwner = BIT(14) }
 
- Protected Member Functions inherited from TObjArray
Bool_t BoundsOk (const char *where, Int_t at) const
 
Int_t GetAbsLast () const
 Return absolute index to last object in array. More...
 
void Init (Int_t s, Int_t lowerBound)
 Initialize a TObjArray. More...
 
Bool_t OutOfBoundsError (const char *where, Int_t i) const
 Generate an out-of-bounds error. Always returns false. More...
 
- Protected Member Functions inherited from TSeqCollection
 TSeqCollection ()
 
virtual void Changed ()
 
- Protected Member Functions inherited from TCollection
 TCollection ()
 
virtual const char * GetCollectionEntryName (TObject *entry) const
 For given collection entry return the string that is used to identify the object and, potentially, perform wildcard/regexp filtering on. More...
 
virtual void PrintCollectionEntry (TObject *entry, Option_t *option, Int_t recurse) const
 Print the collection entry. More...
 
virtual void PrintCollectionHeader (Option_t *option) const
 Print the collection header. More...
 
- Protected Member Functions inherited from TObject
virtual void DoError (int level, const char *location, const char *fmt, va_list va) const
 Interface to ErrorHandler (protected). More...
 
void MakeZombie ()
 

#include <TClonesArray.h>

Inheritance diagram for TClonesArray:
[legend]

Member Enumeration Documentation

anonymous enum

Saved copies of pointers to objects.

Enumerator
kForgetBits 
kNoSplit 
kBypassStreamer 

Definition at line 39 of file TClonesArray.h.

Constructor & Destructor Documentation

TClonesArray::TClonesArray ( )

Default Constructor.

Definition at line 159 of file TClonesArray.cxx.

TClonesArray::TClonesArray ( const char *  classname,
Int_t  s = 1000,
Bool_t  call_dtor = kFALSE 
)

Create an array of clone objects of classname.

The class must inherit from TObject. The second argument s indicates an approximate number of objects that will be entered in the array. If more than s objects are entered, the array will be automatically expanded.

The third argument is not used anymore and only there for backward compatibility reasons.

Definition at line 175 of file TClonesArray.cxx.

TClonesArray::TClonesArray ( const TClass cl,
Int_t  s = 1000,
Bool_t  call_dtor = kFALSE 
)

Create an array of clone objects of class cl.

The class must inherit from TObject. The second argument, s, indicates an approximate number of objects that will be entered in the array. If more than s objects are entered, the array will be automatically expanded.

The third argument is not used anymore and only there for backward compatibility reasons.

Definition at line 191 of file TClonesArray.cxx.

TClonesArray::TClonesArray ( const TClonesArray tc)

Copy ctor.

Definition at line 200 of file TClonesArray.cxx.

TClonesArray::~TClonesArray ( )
virtual

Delete a clones array.

Definition at line 252 of file TClonesArray.cxx.

Member Function Documentation

void TClonesArray::AbsorbObjects ( TClonesArray tc)

Directly move the object pointers from tc without cloning (copying).

This TClonesArray takes over ownership of all of tc's object pointers. The tc array is left empty upon return.

Definition at line 931 of file TClonesArray.cxx.

void TClonesArray::AbsorbObjects ( TClonesArray tc,
Int_t  idx1,
Int_t  idx2 
)

Directly move the range of object pointers from tc without cloning (copying).

This TClonesArray takes over ownership of all of tc's object pointers from idx1 to idx2. The tc array is re-arranged by return.

Definition at line 944 of file TClonesArray.cxx.

void TClonesArray::AddAfter ( const TObject after,
TObject obj 
)
inlinevirtual

Add object in the slot after object after.

If after=0 add object in the last empty slot. Note that this will overwrite any object that might have already been in this slot. For insertion semantics use either a TList or a TOrdCollection.

Reimplemented from TObjArray.

Definition at line 65 of file TClonesArray.h.

void TClonesArray::AddAt ( TObject obj,
Int_t  idx 
)
inlinevirtual

Add object at position ids.

Give an error when idx is out of bounds (i.e. the array is not expanded).

Reimplemented from TObjArray.

Definition at line 62 of file TClonesArray.h.

void TClonesArray::AddAtAndExpand ( TObject obj,
Int_t  idx 
)
inlinevirtual

Add object at position idx.

If idx is larger than the current size of the array, expand the array (double its size).

Reimplemented from TObjArray.

Definition at line 63 of file TClonesArray.h.

Int_t TClonesArray::AddAtFree ( TObject obj)
inlinevirtual

Return the position of the new object.

Find the first empty cell or AddLast if there is no empty cell

Reimplemented from TObjArray.

Definition at line 64 of file TClonesArray.h.

void TClonesArray::AddBefore ( const TObject before,
TObject obj 
)
inlinevirtual

Add object in the slot before object before.

If before=0 add object in the first slot. Note that this will overwrite any object that might have already been in this slot. For insertion semantics use either a TList or a TOrdCollection.

Reimplemented from TObjArray.

Definition at line 66 of file TClonesArray.h.

void TClonesArray::AddFirst ( TObject obj)
inlinevirtual

Add object in the first slot of the array.

This will overwrite the first element that might have been there. To have insertion semantics use either a TList or a TOrdCollection.

Reimplemented from TObjArray.

Definition at line 60 of file TClonesArray.h.

void TClonesArray::AddLast ( TObject obj)
inlinevirtual

Add object in the next empty slot in the array.

Expand the array if necessary.

Reimplemented from TObjArray.

Definition at line 61 of file TClonesArray.h.

TObject * TClonesArray::AddrAt ( Int_t  idx)
inline

Definition at line 90 of file TClonesArray.h.

void TClonesArray::BypassStreamer ( Bool_t  bypass = kTRUE)

When the kBypassStreamer bit is set, the automatically generated Streamer can call directly TClass::WriteBuffer.

Bypassing the Streamer improves the performance when writing/reading the objects in the TClonesArray. However there is a drawback: When a TClonesArray is written with split=0 bypassing the Streamer, the StreamerInfo of the class in the array being optimized, one cannot use later the TClonesArray with split>0. For example, there is a problem with the following scenario:

  1. A class Foo has a TClonesArray of Bar objects
  2. The Foo object is written with split=0 to Tree T1. In this case the StreamerInfo for the class Bar is created in optimized mode in such a way that data members of the same type are written as an array improving the I/O performance.
  3. In a new program, T1 is read and a new Tree T2 is created with the object Foo in split>1
  4. When the T2 branch is created, the StreamerInfo for the class Bar is created with no optimization (mandatory for the split mode). The optimized Bar StreamerInfo is going to be used to read the TClonesArray in T1. The result will be Bar objects with data member values not in the right sequence. The solution to this problem is to call BypassStreamer(kFALSE) for the TClonesArray. In this case, the normal Bar::Streamer function will be called. The Bar::Streamer function works OK independently if the Bar StreamerInfo had been generated in optimized mode or not.

Definition at line 292 of file TClonesArray.cxx.

Bool_t TClonesArray::CanBypassStreamer ( ) const
inline

Definition at line 68 of file TClonesArray.h.

void TClonesArray::Clear ( Option_t option = "")
virtual

Clear the clones array.

Only use this routine when your objects don't allocate memory since it will not call the object dtors. However, if the class in the TClonesArray implements the function Clear(Option_t *option) and if option = "C" the function Clear() is called for all objects in the array. In the function Clear(), one can delete objects or dynamic arrays allocated in the class. This procedure is much faster than calling TClonesArray::Delete(). When the option starts with "C+", eg "C+xyz" the objects in the array are in turn cleared with the option "xyz"

Reimplemented from TObjArray.

Definition at line 391 of file TClonesArray.cxx.

void TClonesArray::Compress ( )
virtual

Remove empty slots from array.

Reimplemented from TObjArray.

Definition at line 303 of file TClonesArray.cxx.

TObject * TClonesArray::ConstructedAt ( Int_t  idx)

Get an object at index 'idx' that is guaranteed to have been constructed.

It might be either a freshly allocated object or one that had already been allocated (and assumingly used). In the later case, it is the callers responsibility to insure that the object is returned to a known state, usually by calling the Clear method on the TClonesArray.

Tests to see if the destructor has been called on the object. If so, or if the object has never been constructed the class constructor is called using New(). If not, return a pointer to the correct memory location. This explicitly to deal with TObject classes that allocate memory which will be reset (but not deallocated) in their Clear() functions.

Definition at line 348 of file TClonesArray.cxx.

TObject * TClonesArray::ConstructedAt ( Int_t  idx,
Option_t clear_options 
)

Get an object at index 'idx' that is guaranteed to have been constructed.

It might be either a freshly allocated object or one that had already been allocated (and assumingly used). In the later case, the function Clear will be called and passed the value of 'clear_options'

Tests to see if the destructor has been called on the object. If so, or if the object has never been constructed the class constructor is called using New(). If not, return a pointer to the correct memory location. This explicitly to deal with TObject classes that allocate memory which will be reset (but not deallocated) in their Clear() functions.

Definition at line 370 of file TClonesArray.cxx.

void TClonesArray::Delete ( Option_t option = "")
virtual

Clear the clones array.

Use this routine when your objects allocate memory (e.g. objects inheriting from TNamed or containing TStrings allocate memory). If not you better use Clear() since if is faster.

Reimplemented from TObjArray.

Definition at line 423 of file TClonesArray.cxx.

void TClonesArray::Expand ( Int_t  newSize)
virtual

Expand or shrink the array to newSize elements.

Reimplemented from TObjArray.

Definition at line 450 of file TClonesArray.cxx.

void TClonesArray::ExpandCreate ( Int_t  n)
virtual

Expand or shrink the array to n elements and create the clone objects by calling their default ctor.

If n is less than the current size the array is shrunk and the allocated space is freed. This routine is typically used to create a clonesarray into which one can directly copy object data without going via the "new (arr[i]) MyObj()" (i.e. the vtbl is already set correctly).

Definition at line 480 of file TClonesArray.cxx.

void TClonesArray::ExpandCreateFast ( Int_t  n)
virtual

Expand or shrink the array to n elements and create the clone objects by calling their default ctor.

If n is less than the current size the array is shrunk but the allocated space is not freed. This routine is typically used to create a clonesarray into which one can directly copy object data without going via the "new (arr[i]) MyObj()" (i.e. the vtbl is already set correctly). This is a simplified version of ExpandCreate used in the TTree mechanism.

Definition at line 520 of file TClonesArray.cxx.

TClass* TClonesArray::GetClass ( ) const
inline

Definition at line 57 of file TClonesArray.h.

void TClonesArray::MultiSort ( Int_t  nTCs,
TClonesArray **  tcs,
Int_t  upto = kMaxInt 
)

Sort multiple TClonesArrays simultaneously with this array.

If objects in array are sortable (i.e. IsSortable() returns true for all objects) then sort array.

Definition at line 1000 of file TClonesArray.cxx.

TObject * TClonesArray::New ( Int_t  idx)

Create an object of type fClass with the default ctor at the specified index.

Returns 0 in case of error.

Definition at line 907 of file TClonesArray.cxx.

TClonesArray & TClonesArray::operator= ( const TClonesArray tc)

Assignment operator.

Definition at line 216 of file TClonesArray.cxx.

TObject *& TClonesArray::operator[] ( Int_t  idx)
virtual

Return pointer to reserved area in which a new object of clones class can be constructed.

This operator should not be used for lefthand side assignments, like a[2] = xxx. Only like, new (a[2]) myClass, or xxx = a[2]. Of course right hand side usage is only legal after the object has been constructed via the new operator or via the New() method. To remove elements from the clones array use Remove() or RemoveAt().

Reimplemented from TObjArray.

Definition at line 859 of file TClonesArray.cxx.

TObject * TClonesArray::operator[] ( Int_t  idx) const
virtual

Return the object at position idx. Returns 0 if idx is out of bounds.

Reimplemented from TObjArray.

Definition at line 893 of file TClonesArray.cxx.

TObject * TClonesArray::Remove ( TObject obj)
virtual

Remove object from array.

Reimplemented from TObjArray.

Definition at line 570 of file TClonesArray.cxx.

TObject * TClonesArray::RemoveAt ( Int_t  idx)
virtual

Remove object at index idx.

Reimplemented from TObjArray.

Definition at line 546 of file TClonesArray.cxx.

void TClonesArray::RemoveRange ( Int_t  idx1,
Int_t  idx2 
)
virtual

Remove objects from index idx1 to idx2 included.

Reimplemented from TObjArray.

Definition at line 593 of file TClonesArray.cxx.

void TClonesArray::SetClass ( const char *  classname,
Int_t  size = 1000 
)

see TClonesArray::SetClass(const TClass*)

Definition at line 664 of file TClonesArray.cxx.

void TClonesArray::SetClass ( const TClass cl,
Int_t  s = 1000 
)

Create an array of clone objects of class cl.

The class must inherit from TObject. The second argument s indicates an approximate number of objects that will be entered in the array. If more than s objects are entered, the array will be automatically expanded.

NB: This function should not be called in the TClonesArray is already initialized with a class.

Definition at line 627 of file TClonesArray.cxx.

void TClonesArray::SetOwner ( Bool_t  enable = kTRUE)
virtual

A TClonesArray is always the owner of the object it contains.

However the collection its inherits from (TObjArray) does not. Hence this member function needs to be a nop for TClonesArray.

Reimplemented from TCollection.

Definition at line 675 of file TClonesArray.cxx.

void TClonesArray::Sort ( Int_t  upto = kMaxInt)
virtual

If objects in array are sortable (i.e.

IsSortable() returns true for all objects) then sort array.

Reimplemented from TObjArray.

Definition at line 684 of file TClonesArray.cxx.

Member Data Documentation

TClass* TClonesArray::fClass
protected

Definition at line 35 of file TClonesArray.h.

TObjArray* TClonesArray::fKeep
protected

Pointer to the class of the elements.

Definition at line 36 of file TClonesArray.h.


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