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THashTable Class Reference

THashTable implements a hash table to store TObject's.

The hash value is calculated using the value returned by the TObject's Hash() function. Each class inheriting from TObject can override Hash() as it sees fit.

THashTable does not preserve the insertion order of the objects. If the insertion order is important AND fast retrieval is needed use THashList instead.

Definition at line 39 of file THashTable.h.

Public Member Functions

 THashTable (Int_t capacity=TCollection::kInitHashTableCapacity, Int_t rehash=0)
 
virtual ~THashTable ()
 Delete a hashtable. More...
 
void Add (TObject *obj)
 Add object to the hash table. More...
 
void AddBefore (const TObject *before, TObject *obj)
 Add object to the hash table. More...
 
virtual void AddAll (const TCollection *col)
 Add all objects from collection col to this collection. More...
 
Float_t AverageCollisions () const
 
void Clear (Option_t *option="")
 Remove all objects from the table. More...
 
Int_t Collisions (const char *name) const
 Returns the number of collisions for an object with a certain name (i.e. More...
 
Int_t Collisions (TObject *obj) const
 Returns the number of collisions for an object (i.e. More...
 
void Delete (Option_t *option="")
 Remove all objects from the table AND delete all heap based objects. More...
 
TObjectFindObject (const char *name) const
 Find object using its name. More...
 
TObjectFindObject (const TObject *obj) const
 Find object using its hash value (returned by its Hash() member). More...
 
const TListGetListForObject (const char *name) const
 Return the TList corresponding to object's name based hash value. More...
 
const TListGetListForObject (const TObject *obj) const
 Return the TList corresponding to object's hash value. More...
 
TObject ** GetObjectRef (const TObject *obj) const
 Return address of pointer to obj. More...
 
Int_t GetRehashLevel () const
 
Int_t GetSize () const
 
TIteratorMakeIterator (Bool_t dir=kIterForward) const
 Returns a hash table iterator. More...
 
void Rehash (Int_t newCapacity, Bool_t checkObjValidity=kTRUE)
 Rehash the hashtable. More...
 
TObjectRemove (TObject *obj)
 Remove object from the hashtable. More...
 
TObjectRemoveSlow (TObject *obj)
 Remove object from the hashtable without using the hash value. More...
 
void SetRehashLevel (Int_t rehash)
 
- Public Member Functions inherited from TCollection
virtual ~TCollection ()
 
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...
 
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...
 
TObjectoperator() (const char *name) const
 Find an object in this collection by name. More...
 
virtual Int_t GetEntries () const
 
virtual const char * GetName () const
 Return name of this collection. More...
 
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 IsEmpty () const
 
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 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 RecursiveRemove (TObject *obj)
 Remove object from this collection and recursively remove the object from all other objects (and collections). 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 void SetOwner (Bool_t enable=kTRUE)
 Set whether this collection is the owner (enable==true) of its content. More...
 
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...
 
TIter begin () const
 
TIter end () const
 
- 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 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 pad. 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 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 const char * GetIconName () const
 Returns mime type name of object. 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 const char * GetTitle () const
 Returns title of object. 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 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...
 
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...
 
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...
 

Private Member Functions

Int_t GetHashValue (const TObject *obj) const
 
Int_t GetHashValue (TString &s) const
 
Int_t GetHashValue (const char *str) const
 
 THashTable (const THashTable &)
 
THashTableoperator= (const THashTable &)
 

Private Attributes

TList ** fCont
 
Int_t fEntries
 
Int_t fUsedSlots
 
Int_t fRehashLevel
 

Friends

class THashTableIter
 

Additional Inherited Members

- Public Types inherited from TCollection
enum  { kInitCapacity = 16, kInitHashTableCapacity = 17 }
 
- 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 TCollection
static TCollectionGetCurrentCollection ()
 Return the globally accessible collection. More...
 
static void StartGarbageCollection ()
 Set up for garbage collection. More...
 
static void GarbageCollect (TObject *obj)
 Add to the list of things to be cleaned up. More...
 
static void EmptyGarbageCollection ()
 Do the garbage collection. More...
 
- 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...
 
- Protected Types inherited from TCollection
enum  { kIsOwner = BIT(14) }
 
- Protected Member Functions inherited from TCollection
 TCollection ()
 
virtual void PrintCollectionHeader (Option_t *option) const
 Print the collection header. More...
 
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...
 
- 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 inherited from TCollection
TString fName
 
Int_t fSize
 

#include <THashTable.h>

Inheritance diagram for THashTable:
[legend]

Constructor & Destructor Documentation

THashTable::THashTable ( const THashTable )
private

Referenced by Rehash().

THashTable::THashTable ( Int_t  capacity = TCollection::kInitHashTableCapacity,
Int_t  rehash = 0 
)
THashTable::~THashTable ( )
virtual

Delete a hashtable.

Objects are not deleted unless the THashTable is the owner (set via SetOwner()).

Definition at line 64 of file THashTable.cxx.

Member Function Documentation

void THashTable::Add ( TObject obj)
virtual
void THashTable::AddAll ( const TCollection col)
virtual

Add all objects from collection col to this collection.

Implemented for more efficient rehashing.

Reimplemented from TCollection.

Definition at line 122 of file THashTable.cxx.

void THashTable::AddBefore ( const TObject before,
TObject obj 
)

Add object to the hash table.

Its position in the table will be determined by the value returned by its Hash() function. If and only if 'before' is in the same bucket as obj, obj is added in front of 'before' within the bucket's list.

Definition at line 98 of file THashTable.cxx.

Referenced by THashList::AddBefore().

Float_t THashTable::AverageCollisions ( ) const
inline
void THashTable::Clear ( Option_t option = "")
virtual

Remove all objects from the table.

Does not delete the objects unless the THashTable is the owner (set via SetOwner()).

Implements TCollection.

Definition at line 149 of file THashTable.cxx.

Referenced by THashList::Clear(), THashList::Delete(), Rehash(), and ~THashTable().

Int_t THashTable::Collisions ( const char *  name) const

Returns the number of collisions for an object with a certain name (i.e.

number of objects in same slot in the hash table, i.e. length of linked list).

Definition at line 171 of file THashTable.cxx.

Referenced by TMap::Collisions().

Int_t THashTable::Collisions ( TObject obj) const

Returns the number of collisions for an object (i.e.

number of objects in same slot in the hash table, i.e. length of linked list).

Definition at line 182 of file THashTable.cxx.

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

Remove all objects from the table AND delete all heap based objects.

Implements TCollection.

Definition at line 194 of file THashTable.cxx.

Referenced by TDictAttributeMap::Clear(), TMap::Clear(), TMap::Delete(), TMap::DeleteAll(), TMap::DeleteValues(), parallelMergeServer(), and TGPicturePool::~TGPicturePool().

TObject * THashTable::FindObject ( const char *  name) const
virtual
TObject * THashTable::FindObject ( const TObject obj) const
virtual

Find object using its hash value (returned by its Hash() member).

Reimplemented from TCollection.

Definition at line 220 of file THashTable.cxx.

Int_t THashTable::GetHashValue ( const TObject obj) const
inlineprivate

Definition at line 91 of file THashTable.h.

Referenced by Add(), AddBefore(), Collisions(), FindObject(), GetListForObject(), GetObjectRef(), and Remove().

Int_t THashTable::GetHashValue ( TString s) const
inlineprivate

Definition at line 50 of file THashTable.h.

Int_t THashTable::GetHashValue ( const char *  str) const
inlineprivate

Definition at line 51 of file THashTable.h.

const TList * THashTable::GetListForObject ( const char *  name) const

Return the TList corresponding to object's name based hash value.

One can iterate this list "manually" to find, e.g. objects with the same name.

Definition at line 234 of file THashTable.cxx.

Referenced by THashList::GetListForObject(), TClass::Init(), and TClass::~TClass().

const TList * THashTable::GetListForObject ( const TObject obj) const

Return the TList corresponding to object's hash value.

One can iterate this list "manually" to find, e.g. identical objects.

Definition at line 244 of file THashTable.cxx.

TObject ** THashTable::GetObjectRef ( const TObject obj) const
virtual

Return address of pointer to obj.

Implements TCollection.

Definition at line 253 of file THashTable.cxx.

Referenced by TMap::GetObjectRef().

Int_t THashTable::GetRehashLevel ( ) const
inline

Definition at line 72 of file THashTable.h.

Int_t THashTable::GetSize ( ) const
inlinevirtual

Reimplemented from TCollection.

Definition at line 73 of file THashTable.h.

Referenced by TDictAttributeMap::GetPropertySize(), Remove(), and RemoveSlow().

TIterator * THashTable::MakeIterator ( Bool_t  dir = kIterForward) const
virtual

Returns a hash table iterator.

Implements TCollection.

Definition at line 265 of file THashTable.cxx.

THashTable& THashTable::operator= ( const THashTable )
private
void THashTable::Rehash ( Int_t  newCapacity,
Bool_t  checkObjValidity = kTRUE 
)

Rehash the hashtable.

If the collision rate becomes too high (i.e. the average size of the linked lists become too long) then lookup efficiency decreases since relatively long lists have to be searched every time. To improve performance rehash the hashtable. This resizes the table to newCapacity slots and refills the table. Use AverageCollisions() to check if you need to rehash. Set checkObjValidity to kFALSE if you know that all objects in the table are still valid (i.e. have not been deleted from the system in the meanwhile).

Definition at line 280 of file THashTable.cxx.

Referenced by Add(), AddAll(), AddBefore(), THashList::Rehash(), and TMap::Rehash().

TObject * THashTable::Remove ( TObject obj)
virtual
TObject * THashTable::RemoveSlow ( TObject obj)

Remove object from the hashtable without using the hash value.

Definition at line 335 of file THashTable.cxx.

Referenced by THashList::RecursiveRemove().

void THashTable::SetRehashLevel ( Int_t  rehash)
inline

Definition at line 78 of file THashTable.h.

Friends And Related Function Documentation

friend class THashTableIter
friend

Definition at line 41 of file THashTable.h.

Referenced by MakeIterator().

Member Data Documentation

TList** THashTable::fCont
private
Int_t THashTable::fEntries
private
Int_t THashTable::fRehashLevel
private

Definition at line 47 of file THashTable.h.

Referenced by Add(), AddAll(), AddBefore(), GetRehashLevel(), Rehash(), and SetRehashLevel().

Int_t THashTable::fUsedSlots
private

Definition at line 46 of file THashTable.h.

Referenced by Add(), AddBefore(), AverageCollisions(), Clear(), Delete(), Rehash(), Remove(), and RemoveSlow().

Collaboration diagram for THashTable:
[legend]

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