// Copyright (c) 2005-2009 Nokia Corporation and/or its subsidiary(-ies).

// All rights reserved.

// This component and the accompanying materials are made available

// under the terms of the License "Eclipse Public License v1.0"

// which accompanies this distribution, and is available

// at the URL "http://www.eclipse.org/legal/epl-v10.html".

//

// Initial Contributors:

// Nokia Corporation - initial contribution.

//

// Contributors:

//

// Description:

// e32/include/e32hashtab.h

// 

//

#ifndef __E32HASHTAB_H__

#define __E32HASHTAB_H__

#include <e32cmn.h>

/**

@publishedAll

@released

Defines a function type used by a THashFunction32 object. 

A function of this type implements an algorithm for producing a 32 bit hash

value from a key.

@see THashFunction32

*/

typedef TUint32 (*TGeneralHashFunction32)(const TAny*);

/**

@publishedAll

@released

A templated class which packages a function that calculates a 32 bit hash

value from a key of templated type.

A THashFunction32<T> object is constructed and passed as a parameter to 

member functions of the hash table classes RHashSet<T>, RPtrHashSet<T>,

RHashMap<T,V> and RPtrHashMap<T,V>.

@see RHashSet

@see RPtrHashSet

@see RHashMap

@see RPtrHashMap

*/

template <class T>

class THashFunction32

	{

public:

	inline THashFunction32( TUint32 (*aHashFunc)(const T&) )

		{ iHashFunction = (TGeneralHashFunction32)aHashFunc; }

	inline operator TGeneralHashFunction32() const

		{ return iHashFunction; }

	inline TUint32 Hash(const T& aKey) const

		{ return (*iHashFunction)(&aKey); }

private:

	TGeneralHashFunction32 iHashFunction;

	};

/**

@publishedAll

@released

A set of common hashing functions for frequently occurring types.

@see RHashSet

@see RPtrHashSet

@see RHashMap

@see RPtrHashMap

*/

class DefaultHash

	{

public:

	IMPORT_C static TUint32 Integer(const TInt&);

	IMPORT_C static TUint32 Des8(const TDesC8&);

	IMPORT_C static TUint32 Des16(const TDesC16&);

	IMPORT_C static TUint32 IntegerPtr(TInt* const &);

	IMPORT_C static TUint32 Des8Ptr(TDesC8* const &);

	IMPORT_C static TUint32 Des16Ptr(TDesC16* const &);

	};

class THashTableIterBase;

/**

@internalComponent

Base class used in the derivation of RHashSet<T>, RPtrHashSet<T>,

RHashMap<K,V> and RPtrHashMap<K,V>.

This class provides a general hash table implementation using probe sequences

generated by pseudo-double hashing.

The class is internal and is not intended for use.

*/

class RHashTableBase

	{

public:

	enum TDefaultSpecifier

		{

		EDefaultSpecifier_Normal,

		};

protected:

	template<class K, TDefaultSpecifier S>

	class Defaults

		{

	public:

		inline static TGeneralHashFunction32 Hash();

		inline static TGeneralIdentityRelation Id();

		};

protected:

	enum TElementState

		{

		EEmpty=0,		// entry is vacant

		EDeleted=1,		// entry has been deleted

		EGen0=2,		// entry is occupied, generation number 0

		EGen1=3,		// entry is occupied, generation number 1

		EStateMask=3,

		EOccupiedMask=2,

		};

	struct SElement

		{

		inline void SetEmpty() {iHash=EEmpty;}

		inline void SetDeleted() {iHash=EDeleted;}

		inline TBool IsEmpty() const {return (iHash&EStateMask)==EEmpty;}

		inline TBool IsDeleted() const {return (iHash&EStateMask)==EDeleted;}

		inline TBool IsEmptyOrDeleted() const {return !(iHash&EOccupiedMask);}

		TUint32	iHash;			// bits 2-31 = 30 bit hash value, bits 0,1 = state

		};

protected:

	IMPORT_C RHashTableBase(TGeneralHashFunction32, TGeneralIdentityRelation, TInt aElementSize, TInt aKeyOffset);

	IMPORT_C void Close();

	IMPORT_C TAny* Find(const TAny* aKey, TInt aOffset=0) const;

	IMPORT_C TAny* FindL(const TAny* aKey, TInt aOffset=0) const;

	TInt Insert(const TAny* aKey, TAny*& aElement);

	IMPORT_C TInt PtrInsert(const TAny* aKey, const TAny* aValue);

	IMPORT_C void PtrInsertL(const TAny* aKey, const TAny* aValue);

	IMPORT_C TInt ValueInsert(const TAny* aKey, TInt aKeySize, const TAny* aValue, TInt aValueOffset, TInt aValueSize);

	IMPORT_C void ValueInsertL(const TAny* aKey, TInt aKeySize, const TAny* aValue, TInt aValueOffset, TInt aValueSize);

	IMPORT_C TInt Remove(const TAny* aKey);

	IMPORT_C TInt Count() const;

	IMPORT_C TInt Reserve(TInt aCount);

	IMPORT_C void ReserveL(TInt aCount);

	IMPORT_C void ConsistencyCheck(TUint32* aDeleted=0, TUint32* aComparisons=0, TUint32 aChainLimit=0, TUint32* aChainInfo=0);

private:

	void SetThresholds();

	TInt ExpandTable(TInt aNewIndexBits);

	void ShrinkTable();

	void ReformTable(TUint aNewIndexBits);

	void VerifyReform();

private:

	inline SElement* Element(TInt aIndex)

		{return (SElement*)(((TUint8*)iElements) + aIndex*iElementSize);}

	inline const SElement* ElementC(TInt aIndex) const

		{return (const SElement*)(((TUint8*)iElements) + aIndex*iElementSize);}

	inline TAny* GetKey(const SElement* aElement) const

		{return iKeyOffset ? ((TUint8*)aElement + iKeyOffset) : (TAny*)((TUint32*)aElement)[1];}

private:

	TGeneralHashFunction32 iHashFunc;	// generates the hash from a given key

	TGeneralIdentityRelation iIdFunc;	// compare two keys for equality

	TUint8 iIndexBits;					// number of bits used to index the table

	TUint8 iGeneration;					// 2 or 3, generation number used when traversing entire table

	TUint8 iKeyOffset;					// offset to key

	TUint8 iPad0;

	TAny* iElements;

	TUint32 iCount;						// number of valid entries

	TUint32 iEmptyCount;				// number of empty entries

	TUint32 iLowerThreshold;			// shrink if count drops below this

	TUint32 iUpperThreshold;			// expand if count rises above this

	TUint32 iCleanThreshold;			// clean table if count of empty entries falls below this

	TInt iElementSize;

	TInt iPad1;							// expansion room

	TInt iPad2;

	friend struct RHashTableBase::SElement;

	friend class THashTableIterBase;

	friend class HashTest;

	};

/**

@internalComponent

*/

TEMPLATE_SPECIALIZATION class RHashTableBase::Defaults<TInt*, RHashTableBase::EDefaultSpecifier_Normal>

	{

public:

	inline static TGeneralHashFunction32 Hash();

	inline static TGeneralIdentityRelation Id();

	};

/**

@internalComponent

*/

inline TGeneralHashFunction32 RHashTableBase::Defaults<TInt*, RHashTableBase::EDefaultSpecifier_Normal>::Hash()

	{return (TGeneralHashFunction32)&DefaultHash::IntegerPtr;}

/**

@internalComponent

*/

inline TGeneralIdentityRelation RHashTableBase::Defaults<TInt*, RHashTableBase::EDefaultSpecifier_Normal>::Id()

	{return (TGeneralIdentityRelation)&DefaultIdentity::IntegerPtr;}

/**

@internalComponent

*/

TEMPLATE_SPECIALIZATION class RHashTableBase::Defaults<TInt32*, RHashTableBase::EDefaultSpecifier_Normal>

	{

public:

	inline static TGeneralHashFunction32 Hash();

	inline static TGeneralIdentityRelation Id();

	};

/**

@internalComponent

*/

inline TGeneralHashFunction32 RHashTableBase::Defaults<TInt32*, RHashTableBase::EDefaultSpecifier_Normal>::Hash()

	{return (TGeneralHashFunction32)&DefaultHash::IntegerPtr;}

/**

@internalComponent

*/

inline TGeneralIdentityRelation RHashTableBase::Defaults<TInt32*, RHashTableBase::EDefaultSpecifier_Normal>::Id()

	{return (TGeneralIdentityRelation)&DefaultIdentity::IntegerPtr;}

/**

@internalComponent

*/

TEMPLATE_SPECIALIZATION class RHashTableBase::Defaults<TUint*, RHashTableBase::EDefaultSpecifier_Normal>

	{

public:

	inline static TGeneralHashFunction32 Hash();

	inline static TGeneralIdentityRelation Id();

	};

/**

@internalComponent

*/

inline TGeneralHashFunction32 RHashTableBase::Defaults<TUint*, RHashTableBase::EDefaultSpecifier_Normal>::Hash()

	{return (TGeneralHashFunction32)&DefaultHash::IntegerPtr;}

/**

@internalComponent

*/

inline TGeneralIdentityRelation RHashTableBase::Defaults<TUint*, RHashTableBase::EDefaultSpecifier_Normal>::Id()

	{return (TGeneralIdentityRelation)&DefaultIdentity::IntegerPtr;}

/**

@internalComponent

*/

TEMPLATE_SPECIALIZATION class RHashTableBase::Defaults<TUint32*, RHashTableBase::EDefaultSpecifier_Normal>

	{

public:

	inline static TGeneralHashFunction32 Hash();

	inline static TGeneralIdentityRelation Id();

	};

/**

@internalComponent

*/

inline TGeneralHashFunction32 RHashTableBase::Defaults<TUint32*, RHashTableBase::EDefaultSpecifier_Normal>::Hash()

	{return (TGeneralHashFunction32)&DefaultHash::IntegerPtr;}

/**

@internalComponent

*/

inline TGeneralIdentityRelation RHashTableBase::Defaults<TUint32*, RHashTableBase::EDefaultSpecifier_Normal>::Id()

	{return (TGeneralIdentityRelation)&DefaultIdentity::IntegerPtr;}

/**

@internalComponent

*/

TEMPLATE_SPECIALIZATION class RHashTableBase::Defaults<TDesC8*, RHashTableBase::EDefaultSpecifier_Normal>

	{

public:

	inline static TGeneralHashFunction32 Hash();

	inline static TGeneralIdentityRelation Id();

	};

/**

@internalComponent

*/

inline TGeneralHashFunction32 RHashTableBase::Defaults<TDesC8*, RHashTableBase::EDefaultSpecifier_Normal>::Hash()

	{return (TGeneralHashFunction32)&DefaultHash::Des8Ptr;}

/**

@internalComponent

*/

inline TGeneralIdentityRelation RHashTableBase::Defaults<TDesC8*, RHashTableBase::EDefaultSpecifier_Normal>::Id()

	{return (TGeneralIdentityRelation)&DefaultIdentity::Des8Ptr;}

/**

@internalComponent

*/

TEMPLATE_SPECIALIZATION class RHashTableBase::Defaults<TDesC16*, RHashTableBase::EDefaultSpecifier_Normal>

	{

public:

	inline static TGeneralHashFunction32 Hash();

	inline static TGeneralIdentityRelation Id();

	};

/**

@internalComponent

*/

inline TGeneralHashFunction32 RHashTableBase::Defaults<TDesC16*, RHashTableBase::EDefaultSpecifier_Normal>::Hash()

	{return (TGeneralHashFunction32)&DefaultHash::Des16Ptr;}

/**

@internalComponent

*/

inline TGeneralIdentityRelation RHashTableBase::Defaults<TDesC16*, RHashTableBase::EDefaultSpecifier_Normal>::Id()

	{return (TGeneralIdentityRelation)&DefaultIdentity::Des16Ptr;}

/**

@internalComponent

*/

TEMPLATE_SPECIALIZATION class RHashTableBase::Defaults<TInt, RHashTableBase::EDefaultSpecifier_Normal>

	{

public:

	inline static TGeneralHashFunction32 Hash();

	inline static TGeneralIdentityRelation Id();

	};

/**

@internalComponent

*/

inline TGeneralHashFunction32 RHashTableBase::Defaults<TInt, RHashTableBase::EDefaultSpecifier_Normal>::Hash()

	{return (TGeneralHashFunction32)&DefaultHash::Integer;}

/**

@internalComponent

*/

inline TGeneralIdentityRelation RHashTableBase::Defaults<TInt, RHashTableBase::EDefaultSpecifier_Normal>::Id()

	{return (TGeneralIdentityRelation)&DefaultIdentity::Integer;}

/**

@internalComponent

*/

TEMPLATE_SPECIALIZATION class RHashTableBase::Defaults<TInt32, RHashTableBase::EDefaultSpecifier_Normal>

	{

public:

	inline static TGeneralHashFunction32 Hash();

	inline static TGeneralIdentityRelation Id();

	};

/**

@internalComponent

*/

inline TGeneralHashFunction32 RHashTableBase::Defaults<TInt32, RHashTableBase::EDefaultSpecifier_Normal>::Hash()

	{return (TGeneralHashFunction32)&DefaultHash::Integer;}

/**

@internalComponent

*/

inline TGeneralIdentityRelation RHashTableBase::Defaults<TInt32, RHashTableBase::EDefaultSpecifier_Normal>::Id()

	{return (TGeneralIdentityRelation)&DefaultIdentity::Integer;}

/**

@internalComponent

*/

TEMPLATE_SPECIALIZATION class RHashTableBase::Defaults<TUint, RHashTableBase::EDefaultSpecifier_Normal>

	{

public:

	inline static TGeneralHashFunction32 Hash();

	inline static TGeneralIdentityRelation Id();

	};

/**

@internalComponent

*/

inline TGeneralHashFunction32 RHashTableBase::Defaults<TUint, RHashTableBase::EDefaultSpecifier_Normal>::Hash()

	{return (TGeneralHashFunction32)&DefaultHash::Integer;}

/**

@internalComponent

*/

inline TGeneralIdentityRelation RHashTableBase::Defaults<TUint, RHashTableBase::EDefaultSpecifier_Normal>::Id()

	{return (TGeneralIdentityRelation)&DefaultIdentity::Integer;}

/**

@internalComponent

*/

TEMPLATE_SPECIALIZATION class RHashTableBase::Defaults<TUint32, RHashTableBase::EDefaultSpecifier_Normal>

	{

public:

	inline static TGeneralHashFunction32 Hash();

	inline static TGeneralIdentityRelation Id();

	};

/**

@internalComponent

*/

inline TGeneralHashFunction32 RHashTableBase::Defaults<TUint32, RHashTableBase::EDefaultSpecifier_Normal>::Hash()

	{return (TGeneralHashFunction32)&DefaultHash::Integer;}

/**

@internalComponent

*/

inline TGeneralIdentityRelation RHashTableBase::Defaults<TUint32, RHashTableBase::EDefaultSpecifier_Normal>::Id()

	{return (TGeneralIdentityRelation)&DefaultIdentity::Integer;}

/**

@internalComponent

*/

TEMPLATE_SPECIALIZATION class RHashTableBase::Defaults<TDesC8, RHashTableBase::EDefaultSpecifier_Normal>

	{

public:

	inline static TGeneralHashFunction32 Hash();

	inline static TGeneralIdentityRelation Id();

	};

/**

@internalComponent

*/

inline TGeneralHashFunction32 RHashTableBase::Defaults<TDesC8, RHashTableBase::EDefaultSpecifier_Normal>::Hash()

	{return (TGeneralHashFunction32)&DefaultHash::Des8;}

/**

@internalComponent

*/

inline TGeneralIdentityRelation RHashTableBase::Defaults<TDesC8, RHashTableBase::EDefaultSpecifier_Normal>::Id()

	{return (TGeneralIdentityRelation)&DefaultIdentity::Des8;}

/**

@internalComponent

*/

TEMPLATE_SPECIALIZATION class RHashTableBase::Defaults<TDesC16, RHashTableBase::EDefaultSpecifier_Normal>

	{

public:

	inline static TGeneralHashFunction32 Hash();

	inline static TGeneralIdentityRelation Id();

	};

/**

@internalComponent

*/

inline TGeneralHashFunction32 RHashTableBase::Defaults<TDesC16, RHashTableBase::EDefaultSpecifier_Normal>::Hash()

	{return (TGeneralHashFunction32)&DefaultHash::Des16;}

/**

@internalComponent

*/

inline TGeneralIdentityRelation RHashTableBase::Defaults<TDesC16, RHashTableBase::EDefaultSpecifier_Normal>::Id()

	{return (TGeneralIdentityRelation)&DefaultIdentity::Des16;}

/**

@internalComponent

Base class used in the derivation of THashSetIter<T>, TPtrHashSetIter<T>,

THashMapIter<K,V> and TPtrHashMapIter<K,V>.

This class provides iteration capability for the hash table classes derived

from RHashTableBase.

The class is internal and is not intended for use.

*/

class THashTableIterBase

	{

protected:

	IMPORT_C THashTableIterBase(const RHashTableBase& aTable);

	IMPORT_C void Reset();

	IMPORT_C const TAny* Next(TInt aOffset=0);

	IMPORT_C const TAny* Current(TInt aOffset=0) const;

	IMPORT_C void RemoveCurrent();

private:

	const RHashTableBase& iTbl;

	TInt iIndex;

	TInt iPad1;							// expansion room

	TInt iPad2;

	};

template <class T> class THashSetIter;

/**

@publishedAll

@released

A templated class which implements an unordered extensional set of objects of

type T using a probe-sequence hash table. The objects are copied into the set

when they are added. A bitwise binary copy is used here, so the type T must

not implement a nontrivial copy constructor.

*/

template <class T>

class RHashSet : public RHashTableBase

	{

private:

	friend class THashSetIter<T>;

	struct SFullElement

		{

		TUint32 iHash;

		T iT;

		};

public:

/**

A class which allows iteration over the elements of a RHashSet<T> class.

The set being iterated over may not be modified while an iteration is in progress

or the iteration operations may malfunction or panic.

@see THashSetIter<T>

*/

	typedef THashSetIter<T> TIter;

/**

Construct a set of objects of type T using a specified hash function and identity relation.

The set is initially empty.

@param	aHash		The hash function used to hash the objects of type T.

@param	aIdentity	The identity relation used to determine if two objects of type T

					should be considered identical.

*/

	inline RHashSet(const THashFunction32<T>& aHash, const TIdentityRelation<T>& aIdentity)

		:	RHashTableBase(aHash, aIdentity, sizeof(SFullElement), _FOFF(SFullElement,iT))

		{}

/**

Construct a set of objects of type T using a default hash function and identity relation.

The set is initially empty.

*/

	inline RHashSet()

		:	RHashTableBase(Defaults<T,EDefaultSpecifier_Normal>::Hash(), Defaults<T,EDefaultSpecifier_Normal>::Id(), sizeof(SFullElement), _FOFF(SFullElement,iT))

		{}

/**

Free all memory used by this set.

Returns the set to the same state it had following construction.

*/

	inline void Close()

		{ RHashTableBase::Close(); }

/**

Locate a specified element in the set.

@param	aKey	The object of type T to search for.

@return			A pointer to the copy of the specified object in the set, if it

				exists. The object may not be modified via this pointer.

				NULL if the specified object is not a member of this set.

*/

	inline const T* Find(const T& aKey) const

		{ return (const T*)RHashTableBase::Find(&aKey, _FOFF(SFullElement,iT)); }

/**

Locate a specified element in the set.

@param	aKey	The object of type T to search for.

@return			A reference to the copy of the specified object in the set, if it

				exists. The object may not be modified via this reference.

@leave			KErrNotFound if the specified object is not a member of this set.

*/

	inline const T& FindL(const T& aKey) const

		{ return *(const T*)RHashTableBase::FindL(&aKey, _FOFF(SFullElement,iT)); }

/**

Locate a specified element in the set.

@param	aKey	The object of type T to search for.

@return			A pointer to the copy of the specified object in the set, if it

				exists. The object may be modified via this pointer. Care should

				be taken not to modify any parts of the object which are used by

				either the hash function or the identity relation for this set.

				If this is done the set may become inconsistent, resulting in

				malfunctions and/or panics at a later time.

				NULL if the specified object is not a member of this set.

*/

	inline T* Find(const T& aKey)

		{ return (T*)RHashTableBase::Find(&aKey, _FOFF(SFullElement,iT)); }

/**

Locate a specified element in the set.

@param	aKey	The object of type T to search for.

@return			A reference to the copy of the specified object in the set, if it

				exists. The object may be modified via this reference. Care should

				be taken not to modify any parts of the object which are used by

				either the hash function or the identity relation for this set.

				If this is done the set may become inconsistent, resulting in

				malfunctions and/or panics at a later time.

@leave			KErrNotFound if the specified object is not a member of this set.

*/

	inline T& FindL(const T& aKey)

		{ return *(T*)RHashTableBase::FindL(&aKey, _FOFF(SFullElement,iT)); }

/**

Insert an element into the set.

If the specified object is not currently a member of the set, a copy of the

object is added to the set and KErrNone is returned.

If the specified object is currently a member of the set, the existing copy

of the object is replaced by the provided object and KErrNone is

returned.

In both cases the object is copied bitwise into the set.

@param	aKey	The object of type T to add to the set.

@return			KErrNone if the object was added successfully.

				KErrNoMemory if memory could not be allocated to store

					the copy of aKey.

*/

	inline TInt Insert(const T& aKey)

		{ return RHashTableBase::ValueInsert(&aKey, sizeof(T), 0, 0, 0); }

/**

Insert an element into the set.

If the specified object is not currently a member of the set, a copy of the

object is added to the set and KErrNone is returned.

If the specified object is currently a member of the set, the existing copy

of the object is replaced by the provided object and KErrNone is

returned.

In both cases the object is copied bitwise into the set.

@param	aKey	The object of type T to add to the set.

@leave			KErrNoMemory if memory could not be allocated to store

					the copy of aKey.

*/

	inline void InsertL(const T& aKey)

		{ RHashTableBase::ValueInsertL(&aKey, sizeof(T), 0, 0, 0); }

/**

Remove an element from the set.

@param	aKey	The object to be removed.

@return			KErrNone if the object was removed successfully.

				KErrNotFound if the object was not present in the set.

*/

	inline TInt Remove(const T& aKey)

		{ return RHashTableBase::Remove(&aKey); }

/**

Query the number of elements in the set.

@return	The number of elements currently in the set.

*/

	inline TInt Count() const

		{ return RHashTableBase::Count(); }

/**

Expand the set to accommodate a specified number of elements.

If the set already has enough space for the specified number of elements, no

action is taken. Any elements already in the set are retained.

@param	aCount	The number of elements for which space should be allocated.

@return	KErrNone if the operation completed successfully.

@return	KErrNoMemory if sufficient memory could not be allocated.

*/

	inline TInt Reserve(TInt aCount)

		{ return RHashTableBase::Reserve(aCount); }

/**

Expand the set to accommodate a specified number of elements.

If the set already has enough space for the specified number of elements, no

action is taken. Any elements already in the set are retained.

@param	aCount	The number of elements for which space should be allocated.

@leave	KErrNoMemory if sufficient memory could not be allocated.

*/

	inline void ReserveL(TInt aCount)

		{ RHashTableBase::ReserveL(aCount); }

	};

/**

@publishedAll

@released

A templated class which allows iteration over the elements of a RHashSet<T>

class.

The set being iterated over may not be modified while an iteration is in progress

or the iteration operations may malfunction or panic.

@see RHashSet<T>

*/

template <class T>

class THashSetIter : public THashTableIterBase

	{

private:

	struct SFullElement

		{

		TUint32 iHash;

		T iT;

		};

public:

/**

Construct an iterator over the specified set.

The iterator starts at conceptual position one before the beginning of the list

being iterated.

@param	aSet	The set to be iterated over.

*/

	inline THashSetIter(const RHashSet<T>& aSet)

		:	THashTableIterBase(aSet)

		{}

/**

Reset the iterator to its initial state.

@param	aSet	The set to be iterated over.

*/

	inline void Reset()

		{ THashTableIterBase::Reset(); }

/**

Return the current position of the iterator.

@return	A pointer to the set member corresponding to the current position of the

		iterator.

		NULL if the iterator has just been constructed or reset, or if it has

		previously reached the end of an iteration.

*/

	inline const T* Current() const

		{ return (const T*)THashTableIterBase::Current(_FOFF(SFullElement,iT)); }

/**

Steps the iterator to the next position.

@return	A pointer to the set member corresponding to the next position of the

		iterator.

		NULL if the iterator has exhausted all the available set elements.

*/

	inline const T* Next()

		{ return (const T*)THashTableIterBase::Next(_FOFF(SFullElement,iT)); }

/**

Removes the element at the current iterator position from the hash table.

If the iterator does not currently point to a valid element, no action is taken.

Note that the iterator position is not altered so it no longer points to a valid

element following the Remove(). It is illegal to call Current() on the iterator

after calling Remove() - the only legal operations are Reset() and Next().

*/

	inline void RemoveCurrent()

		{ THashTableIterBase::RemoveCurrent(); }

	};

template <class T> class TPtrHashSetIter;

/**

@publishedAll

@released

A templated class which implements an unordered extensional set of objects of

type T using a probe-sequence hash table. The objects are not copied into the set

when they are added; rather the set stores pointers to the contained objects.

*/

template <class T>

class RPtrHashSet : public RHashTableBase

	{

private:

	friend class TPtrHashSetIter<T>;

	struct SFullElement

		{

		TUint32 iHash;

		T* iT;

		};

public:

/**

A class which allows iteration over the elements of a RPtrHashSet<T> class.

The set being iterated over may not be modified while an iteration is in progress

or the iteration operations may malfunction or panic.

@see TPtrHashSetIter<T>

*/

	typedef TPtrHashSetIter<T> TIter;

/**

Construct a set of objects of type T using a specified hash function and identity relation.

The set is initially empty.

@param	aHash		The hash function used to hash the objects of type T.

@param	aIdentity	The identity relation used to determine if two objects of type T

					should be considered identical.

*/

	inline RPtrHashSet(const THashFunction32<T>& aHash, const TIdentityRelation<T>& aIdentity)

		:	RHashTableBase(aHash, aIdentity, sizeof(SFullElement), 0)

		{}

/**

Construct a set of objects of type T using a default hash function and identity relation.

The set is initially empty.

*/

	inline RPtrHashSet()

		:	RHashTableBase(Defaults<T,EDefaultSpecifier_Normal>::Hash(), Defaults<T,EDefaultSpecifier_Normal>::Id(), sizeof(SFullElement), 0)

		{}

/**

Free all memory used by this set.

Returns the set to the same state it had following construction.

*/

	inline void Close()

		{ RHashTableBase::Close(); }

/**

Locate a specified element in the set.

@param	aKey	The object of type T to search for.

@return			A pointer to the specified object, if it is in the set.

				The object may not be modified via this pointer.

				NULL if the specified object is not a member of this set.

*/

	inline const T* Find(const T& aKey) const

		{ return (const T*)RHashTableBase::Find(&aKey, -_FOFF(SFullElement,iT)); }

/**

Locate a specified element in the set.

@param	aKey	The object of type T to search for.

@return			A reference to the specified object, if it is in the set.

				The object may not be modified via this reference.

@leave	KErrNotFound if the specified object is not a member of this set.

*/

	inline const T& FindL(const T& aKey) const

		{ return *(const T*)RHashTableBase::FindL(&aKey, -_FOFF(SFullElement,iT)); }

/**

Locate a specified element in the set.

@param	aKey	The object of type T to search for.

@return			A pointer to the specified object, if it is in the set.

				The object may be modified via this pointer. Care should

				be taken not to modify any parts of the object which are used by

				either the hash function or the identity relation for this set.

				If this is done the set may become inconsistent, resulting in

				malfunctions and/or panics at a later time.

				NULL if the specified object is not a member of this set.

*/

	inline T* Find(const T& aKey)

		{ return (T*)RHashTableBase::Find(&aKey, -_FOFF(SFullElement,iT)); }

/**

Locate a specified element in the set.

@param	aKey	The object of type T to search for.

@return			A reference to the specified object, if it is in the set.

				The object may be modified via this reference. Care should

				be taken not to modify any parts of the object which are used by

				either the hash function or the identity relation for this set.

				If this is done the set may become inconsistent, resulting in

				malfunctions and/or panics at a later time.

@leave	KErrNotFound if the specified object is not a member of this set.

*/

	inline T& FindL(const T& aKey)

		{ return *(T*)RHashTableBase::FindL(&aKey, -_FOFF(SFullElement,iT)); }

/**

Insert an element into the set.

If the specified object is not currently a member of the set, a pointer to the

object is added to the set and KErrNone is returned.

If the specified object is currently a member of the set, the existing pointer

to the object is replaced by the provided pointer and KErrNone is

returned.

In both cases only a pointer to the object is stored - the object is never copied.

@param	aKey	A pointer to the object of type T to add to the set.

@return			KErrNone if the object was added successfully.

				KErrNoMemory if memory could not be allocated to store

					the pointer to the new object.

*/

	inline TInt Insert(const T* aKey)

		{ return RHashTableBase::PtrInsert(aKey, 0); }

/**

Insert an element into the set.

If the specified object is not currently a member of the set, a pointer to the

object is added to the set and KErrNone is returned.

If the specified object is currently a member of the set, the existing pointer

to the object is replaced by the provided pointer and KErrNone is

returned.

In both cases only a pointer to the object is stored - the object is never copied.

@param	aKey	A pointer to the object of type T to add to the set.

@leave	KErrNoMemory if memory could not be allocated to store the pointer to the new object.

*/

	inline void InsertL(const T* aKey)

		{ RHashTableBase::PtrInsertL(aKey, 0); }

/**

Remove an element from the set.

@param	aKey	A pointer to the object to be removed.

@return			KErrNone if the object was removed successfully.

				KErrNotFound if the object was not present in the set.

*/

	inline TInt Remove(const T* aKey)

		{ return RHashTableBase::Remove(aKey); }

/**

Query the number of elements in the set.

@return	The number of elements currently in the set.

*/

	inline TInt Count() const

		{ return RHashTableBase::Count(); }

/**

Expand the set to accommodate a specified number of elements.

If the set already has enough space for the specified number of elements, no

action is taken. Any elements already in the set are retained.

@param	aCount	The number of elements for which space should be allocated.

@return	KErrNone if the operation completed successfully.

@return	KErrNoMemory if sufficient memory could not be allocated.

*/

	inline TInt Reserve(TInt aCount)

		{ return RHashTableBase::Reserve(aCount); }

/**

Expand the set to accommodate a specified number of elements.

If the set already has enough space for the specified number of elements, no

action is taken. Any elements already in the set are retained.

@param	aCount	The number of elements for which space should be allocated.

@leave	KErrNoMemory if sufficient memory could not be allocated.

*/

	inline void ReserveL(TInt aCount)

		{ RHashTableBase::ReserveL(aCount); }

	void ResetAndDestroy();

	};

/**

@publishedAll

@released

A templated class which allows iteration over the elements of a RPtrHashSet<T>

class.

The set being iterated over may not be modified while an iteration is in progress

or the iteration operations may malfunction or panic.

@see RPtrHashSet<T>

*/