nsTHashtable< EntryType > Class Template Reference

#include <nsTHashtable.h>

Inheritance diagram for nsTHashtable< EntryType >:

Collaboration diagram for nsTHashtable< EntryType >:

Detailed Description

template<class EntryType>
class nsTHashtable< EntryType >

Clients will rarely need to use this class directly. Check the derived classes first, to see if they will meet your needs.

Parameters:

EntryType

the templated entry-type class that is managed by the hashtable. EntryType must extend the following declaration, and must not declare any virtual functions or derive from classes with virtual functions. Any vtable pointer would break the PLDHashTable code.

   class EntryType : public PLDHashEntryHdr
   {
   public: or friend nsTHashtable<EntryType>;
     // KeyType is what we use when Get()ing or Put()ing this entry
     // this should either be a simple datatype (PRUint32, nsISupports*) or
     // a const reference (const nsAString&)
     typedef something KeyType;
     // KeyTypePointer is the pointer-version of KeyType, because pldhash.h
     // requires keys to cast to const void*
     typedef const something* KeyTypePointer;

EntryType(KeyTypePointer aKey);

     // the copy constructor must be defined, even if AllowMemMove() == true
     // or you will cause link errors!
     EntryType(const EntryType& aEnt);

     // the destructor must be defined... or you will cause link errors!
     ~EntryType();

     // KeyEquals(): does this entry match this key?
     PRBool KeyEquals(KeyTypePointer aKey) const;

     // KeyToPointer(): Convert KeyType to KeyTypePointer
     static KeyTypePointer KeyToPointer(KeyType aKey);

     // HashKey(): calculate the hash number
     static PLDHashNumber HashKey(KeyTypePointer aKey);

     // ALLOW_MEMMOVE can we move this class with memmove(), or do we have
     // to use the copy constructor?
     enum { ALLOW_MEMMOVE = PR_(TRUE or FALSE) };
   }

See also:

nsInterfaceHashtable

nsDataHashtable

nsClassHashtable

Author:: "Benjamin Smedberg <bsmedberg@covad.net>"


Public Types
typedef EntryType::KeyType	KeyType
	KeyType is typedef'ed for ease of use.
typedef EntryType::KeyTypePointer	KeyTypePointer
	KeyTypePointer is typedef'ed for ease of use.
typedef PLDHashOperator(*	PR_CALLBACK )(EntryType aEntry, void userArg)
	client must provide an `Enumerator` function for EnumerateEntries
Public Member Functions
	nsTHashtable ()
	A dummy constructor; you must call Init() before using this class.
	~nsTHashtable ()
	destructor, cleans up and deallocates
PRBool	Init (PRUint32 initSize=PL_DHASH_MIN_SIZE)
	Initialize the table.
PRBool	IsInitialized () const
	Check whether the table has been initialized.
PRUint32	Count () const
	Return the number of entries in the table.
EntryType *	GetEntry (KeyType aKey) const
	Get the entry associated with a key.
EntryType *	PutEntry (KeyType aKey)
	Get the entry associated with a key, or create a new entry,.
void	RemoveEntry (KeyType aKey)
	Remove the entry associated with a key.
void	RawRemoveEntry (EntryType *aEntry)
	Remove the entry associated with a key, but don't resize the hashtable.
PRUint32	EnumerateEntries (Enumerator enumFunc, void *userArg)
	Enumerate all the entries of the function.
void	Clear ()
	remove all entries, return hashtable to "pristine" state ;)
Static Protected Member Functions
static const void *PR_CALLBACK	s_GetKey (PLDHashTable table, PLDHashEntryHdr entry)
static PLDHashNumber PR_CALLBACK	s_HashKey (PLDHashTable table, const void key)
static PRBool PR_CALLBACK	s_MatchEntry (PLDHashTable table, const PLDHashEntryHdr entry, const void *key)
static void PR_CALLBACK	s_CopyEntry (PLDHashTable table, const PLDHashEntryHdr from, PLDHashEntryHdr *to)
static void PR_CALLBACK	s_ClearEntry (PLDHashTable table, PLDHashEntryHdr entry)
static PRBool PR_CALLBACK	s_InitEntry (PLDHashTable table, PLDHashEntryHdr entry, const void *key)
static PLDHashOperator PR_CALLBACK	s_EnumStub (PLDHashTable table, PLDHashEntryHdr entry, PRUint32 number, void *arg)
Protected Attributes
PLDHashTable	mTable
Classes
struct	s_EnumArgs
	passed internally during enumeration. More...

Member Typedef Documentation

template<class EntryType>

typedef EntryType::KeyType nsTHashtable< EntryType >::KeyType

template<class EntryType>

typedef EntryType::KeyTypePointer nsTHashtable< EntryType >::KeyTypePointer

template<class EntryType>

typedef PLDHashOperator(* nsTHashtable< EntryType >::PR_CALLBACK)(EntryType *aEntry, void *userArg)

Parameters:

	aEntry	the entry being enumerated
	userArg	passed unchanged from `EnumerateEntries`

Returns:: combination of flags PL_DHASH_NEXT , PL_DHASH_STOP , PL_DHASH_REMOVE

Constructor & Destructor Documentation

template<class EntryType>

nsTHashtable< EntryType >::nsTHashtable ( ) [inline]

template<class EntryType>

nsTHashtable< EntryType >::~nsTHashtable ( ) [inline]

Member Function Documentation

template<class EntryType>

PRBool nsTHashtable< EntryType >::Init ( PRUint32 initSize = PL_DHASH_MIN_SIZE ) [inline]

This function must be called before any other class operations. This can fail due to OOM conditions.

Parameters:

initSize

the initial number of buckets in the hashtable, default 16

Returns:: PR_TRUE if the class was initialized properly.

template<class EntryType>

PRBool nsTHashtable< EntryType >::IsInitialized ( ) const [inline]

This can be useful for static hashtables.

Returns:: the initialization state of the class.

template<class EntryType>

PRUint32 nsTHashtable< EntryType >::Count ( ) const [inline]

Returns:: number of entries

template<class EntryType>

EntryType* nsTHashtable< EntryType >::GetEntry ( KeyType aKey ) const [inline]

Parameters:

aKey

the key to retrieve

Returns:: pointer to the entry class, if the key exists; nsnull if the key doesn't exist

template<class EntryType>

EntryType* nsTHashtable< EntryType >::PutEntry ( KeyType aKey ) [inline]

Parameters:

aKey

the key to retrieve

Returns:: pointer to the entry class retreived; nsnull only if memory can't be allocated

template<class EntryType>

void nsTHashtable< EntryType >::RemoveEntry ( KeyType aKey ) [inline]

Parameters:

aKey

of the entry to remove

template<class EntryType>

void nsTHashtable< EntryType >::RawRemoveEntry ( EntryType * aEntry ) [inline]

This is a low-level method, and is not recommended unless you know what you're doing and you need the extra performance. This method can be used during enumeration, while RemoveEntry() cannot.

Parameters:

aEntry

the entry-pointer to remove (obtained from GetEntry or the enumerator

template<class EntryType>

PRUint32 nsTHashtable< EntryType >::EnumerateEntries	(	Enumerator	enumFunc,
		void *	userArg
	)			`[inline]`

Parameters:

	enumFunc	the `Enumerator` function to call
	userArg	a pointer to pass to the `Enumerator` function

Returns:: the number of entries actually enumerated

template<class EntryType>

void nsTHashtable< EntryType >::Clear ( ) [inline]

template<class EntryType>

static const void* PR_CALLBACK nsTHashtable< EntryType >::s_GetKey	(	PLDHashTable *	table,
		PLDHashEntryHdr *	entry
	)			`[static, protected]`

template<class EntryType>

PLDHashNumber nsTHashtable< EntryType >::s_HashKey	(	PLDHashTable *	table,
		const void *	key
	)			`[inline, static, protected]`

template<class EntryType>

PRBool nsTHashtable< EntryType >::s_MatchEntry	(	PLDHashTable *	table,
		const PLDHashEntryHdr *	entry,
		const void *	key
	)			`[inline, static, protected]`

template<class EntryType>

void nsTHashtable< EntryType >::s_CopyEntry	(	PLDHashTable *	table,
		const PLDHashEntryHdr *	from,
		PLDHashEntryHdr *	to
	)			`[inline, static, protected]`

template<class EntryType>

void nsTHashtable< EntryType >::s_ClearEntry	(	PLDHashTable *	table,
		PLDHashEntryHdr *	entry
	)			`[inline, static, protected]`

template<class EntryType>

PRBool nsTHashtable< EntryType >::s_InitEntry	(	PLDHashTable *	table,
		PLDHashEntryHdr *	entry,
		const void *	key
	)			`[inline, static, protected]`

template<class EntryType>

PLDHashOperator nsTHashtable< EntryType >::s_EnumStub	(	PLDHashTable *	table,
		PLDHashEntryHdr *	entry,
		PRUint32	number,
		void *	arg
	)			`[inline, static, protected]`

Member Data Documentation

template<class EntryType>

PLDHashTable nsTHashtable< EntryType >::mTable [protected]

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

xpcom/glue/nsTHashtable.h

nsTHashtable< EntryType > Class Template Reference

Detailed Description

template<class EntryType> class nsTHashtable< EntryType >

Public Types

Public Member Functions

Static Protected Member Functions

Protected Attributes

Classes

Member Typedef Documentation

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation

template<class EntryType>
class nsTHashtable< EntryType >