UaServerHashTable

Data Structures
struct	_UaServer_TableEntry
	A UaServer TableEntry Struct. More...
struct	_UaServer_HashTable
	A UaServer HashTable Struct. More...

Functions
OpcUa_Void	UaServer_HashTable_Initialize (UaServer_HashTable *pTable, size_t 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, unsigned int index, OpcUa_Void *pData)
	Adds the given value pData to the hash table at position index.
OpcUa_StatusCode	UaServer_HashTable_RemoveAt (UaServer_HashTable *pTable, unsigned int index, OpcUa_Void *pData)
	Removes the given value pData from the hash table at position index.
UaServer_TableEntry *	UaServer_HashTable_GetAt (UaServer_HashTable *pTable, unsigned 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.

Detailed Description

Function Documentation

OpcUa_Void UaServer_HashTable_AddAt	(	UaServer_HashTable *	pTable,
		unsigned 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	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	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,
		unsigned 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.

OpcUa_Void UaServer_HashTable_Initialize	(	UaServer_HashTable *	pTable,
		size_t	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.

1. It generates the hash for the key to find the element by direct index access in the table.
2. 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_StatusCode UaServer_HashTable_RemoveAt	(	UaServer_HashTable *	pTable,
		unsigned int	index,
		OpcUa_Void *	pData
	)

Removes the given value pData from the hash table at position index.

Parameters

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

Returns

the OPC UA Status code.

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