UaServerHashTable


Data Structures
struct	_UaServer_TableEntry
	A UaServer TableEntry Struct. More...
struct	_UaServer_HashTable
	A UaServer HashTable Struct. More...
Typedefs
typedef struct _UaServer_TableEntry	UaServer_TableEntry
	A UaServer TableEntry Struct.
typedef struct _UaServer_HashTable	UaServer_HashTable
	A UaServer HashTable Struct.
Functions
OpcUa_Void	UaServer_HashTable_Initialize (UaServer_HashTable *pTable, int size, pt2GetKeyFromValue fctPtr)
	Initializes a hash table.
OpcUa_Void	UaServer_HashTable_Cleanup (UaServer_HashTable *pTable)
	Cleans up hash table struct.
OpcUa_Void	UaServer_HashTable_AddElement (UaServer_HashTable pTable, char szKey, OpcUa_Void *pData)
	Adds the given value pData with the key pKey to the hash table.
OpcUa_Void	UaServer_HashTable_AddAt (UaServer_HashTable pTable, int index, OpcUa_Void pData)
	Adds the given value pData to the hash table at position index.
UaServer_TableEntry *	UaServer_HashTable_GetAt (UaServer_HashTable *pTable, int index)
	Returns the table entry at the given position.
OpcUa_Void *	UaServer_HashTable_RemoveElement (UaServer_HashTable pTable, char szKey)
	Removes the given element from hash table and returns it.
OpcUa_Void *	UaServer_HashTable_Lookup (UaServer_HashTable pTable, char szKey)
	Looks up the given element from hash table and returns it.
unsigned int	UaServer_HashTable_HashString (UaServer_HashTable pTable, char szKey)
	Simple wrapper function for hashing strings.
unsigned int	UaServer_HashTable_Hash (UaServer_HashTable pTable, OpcUa_Void pKey, OpcUa_UInt32 iKeyLen)
	Rotating hash algorithm.

Function Documentation

OpcUa_Void UaServer_HashTable_AddAt	(	UaServer_HashTable *	pTable,
		int	index,
		OpcUa_Void *	pData
	)

Adds the given value pData to the hash table at position index.

This is used for prehashed keys or index based data. The differences to a simple array is that this function still uses the hash table's collision reduction stratagy and you can add multiple items at the same position without an error.

Parameters:

	pTable	hash table object
	index	index where the value is stored.
	pData	data to add

See also:: UaServer_HashTable_Lookup

This is used for prehashed keys or index based data. The differences to a simple array is that this function still uses the hash table's collision reduction stratagy and you can add multiple items at the same position without an error.

Parameters:

	pTable	hash table object
	index	index where the value is stored.
	pData	value to add

See also:: UaServer_HashTable_Lookup

OpcUa_Void UaServer_HashTable_AddElement	(	UaServer_HashTable *	pTable,
		char *	szKey,
		OpcUa_Void *	pData
	)

Adds the given value pData with the key pKey to the hash table.

Parameters:

	pTable	hash table object
	szKey	key which identifies the value
	pData	data to add

See also:: UaServer_HashTable_Lookup

Parameters:

	pTable	hash table object
	szKey	key which identifies the value
	pData	value to add

See also:: UaServer_HashTable_Lookup

OpcUa_Void UaServer_HashTable_Cleanup ( UaServer_HashTable * pTable )

Cleans up hash table struct.

This deletes all memory allocated by hash table, but not the data referenced by the table.

Parameters:

pTable

hash table object

UaServer_TableEntry * UaServer_HashTable_GetAt	(	UaServer_HashTable *	pTable,
		int	index
	)

Returns the table entry at the given position.

Use this to iterate over the list yourself.

Parameters:

	pTable	hash table object that should be initialized.
	index	index where the value is stored.

Returns:: the table entry at the given position.

Use this to iterate over the list yourself.

unsigned int UaServer_HashTable_Hash	(	UaServer_HashTable *	pTable,
		OpcUa_Void *	pKey,
		OpcUa_UInt32	iKeyLen
	)

Rotating hash algorithm.

This simple and fast algorithm is ideal for hash table searches. It's not a cryptographic hash!

 !!! 'int' is used consciously instead of OpcUa_Int32,
 !!! because the hash is an array index,
 !!! which is 'int' by definition (address bus width).

This works for 16, 32 and 64 bit systems.

Parameters:

	pTable	hash table object that should be initialized.
	pKey	key which identifies the value
	iKeyLen	the length of the key.

Returns:: Rotating hash algorithm.

This simple and fast algorithm is ideal for hash table searches. It's not a cryptographic hash!

 !!! 'int' is used consciously instead of OpcUa_Int32,
 !!! because the hash is an array index,
 !!! which is 'int' by definition (address bus width).

This works for 16, 32 and 64 bit systems.

unsigned int UaServer_HashTable_HashString	(	UaServer_HashTable *	pTable,
		char *	szKey
	)

Simple wrapper function for hashing strings.

You can configure this to work case sensitive or case insensitive, by using the define CASE_SENSITIVE. The first variant is much faster.

See also:: UaServer_HashTable_Hash

OpcUa_Void UaServer_HashTable_Initialize	(	UaServer_HashTable *	pTable,
		int	size,
		pt2GetKeyFromValue	fctPtr
	)

Initializes a hash table.

Parameters:

	pTable	hash table object that should be initialized.
	size	Size of hash table. Use a predefined size HASH_SIZE_XXX.
	fctPtr	function pointer to function that retrieves the key string from the data value.

OpcUa_Void * UaServer_HashTable_Lookup	(	UaServer_HashTable *	pTable,
		char *	szKey
	)

Looks up the given element from hash table and returns it.

It generates the hash for the key to find the element by direct index access in the table.
If there is only one element at this index, this gets returned. If there are more elements (hash collision), the elements in list are searched by linear probing.

Parameters:

	pTable	hash table object
	szKey	key to search for

Returns:: found element or OpcUa_Null if not found

OpcUa_Void * UaServer_HashTable_RemoveElement	(	UaServer_HashTable *	pTable,
		char *	szKey
	)

Removes the given element from hash table and returns it.

It searches the element simalar to UaServer_HashTable_Lookup, removes the entry from table and returns the data value.

Parameters:

	pTable	hash table object
	szKey	key to search for

Returns:: removed element or OpcUa_Null if not found

See also:: UaServer_HashTable_Lookup

UaServerHashTable

Data Structures

Typedefs

Functions

Function Documentation