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System CATHashTable

Usage: you must use this class as is. You should never derive it.

public class CATHashTable

Class to define a hash table.
Role:The class collection you will obtain will gain benefits of C++ strong type checking, but its designed to reduce executable code size and to fasten heavily used operations. This table is not ordered, contains no duplicate elements and no null elements.
It is up to you to provide the dimension, the hash-code function and the compare function for each instance of hash table. Only the underlying infrastructure is offered.

Constructor and Destructor Index

o CATHashTable(CATHashTable&): Constructs a new hash table from an another one.
o CATHashTable(CATCollec::PFHash,CATCollec::PFCompare,int): Constructs an empty hash table.
o ~CATHashTable()

Method Index

o Collisions(): Returns the count of item not directly accessible in a hash table.
o Dimension(): Returns the number of bucket in the hash table.
o Insert(void*): Inserts an item in the hash table.
o KeyLocate(CATHashKey): Returns the item with has a given hash value key.
o KeyLocatePosition(CATHashKey,int&,int&): Returns the item with has a given hash value key.
o Locate(void*): Returns an item from a key corresponding to an another item.
o LocatePosition(void*,int&,int&): Returns an item from a key corresponding to an another item.
o Next(void*): Returns the next item given a key in a hash table.
o Next(int&,int&): Returns the next item given a position in a hash table.
o Remove(void*): Removes an item in the hash table.
o RemoveAll(): Removes all elements in the hash table.
o RemovePosition(int,int): Removes an item in the hash table.
o Retrieve(int,int): Retrieves an item from its Bucket and Position in a hash table.
o Size(): Returns the count of item in the hash table.
o Unused(): Returns the count of unused buckets in an hash table.

Constructor and Destructor

o CATHashTable

public CATHashTable( const iCopy)

Constructs a new hash table from an another one.
Role: This new table as same characteristics and contents is copied.

Parameters:

iCopy: The hash table to duplicate

o CATHashTable

public CATHashTable(	`iPFH`,
	`iPFC`,
	`iDimension`	`= 10` )

Constructs an empty hash table.
Role:Constructs an empty hash table of dimension iDimension.
The hash table contains X buckets, X is defined from iDimension. An item is inserted in a bucked according to its key hash value. A bucket can contain several items with not the same key.

Parameters:

iPFH: Pointeur on a global hashing function. This function must returned a key of each element of the table.
iPFC: Pointeur on a global comparison function. This function must return 0 if both instance of the table are equal.
iDimension: Helps specifying the number of bucket (cells receiving 0 to N items) and this number will not vary up to the destruction of the hash table.
Default value:10

o ~CATHashTable

public ~CATHashTable(

)

Methods

o Collisions

public Collisions(

)

Returns the count of item not directly accessible in a hash table.
Role: Item directly accessible are those at the first position in a bucket.

o Dimension

public Dimension(

)

Returns the number of bucket in the hash table.
Role:This number is also the maximum number of items without collisions.

o Insert

public Insert( iAdd)

Inserts an item in the hash table.
Role:Inserts an item according to its key in the table. The key is computed with the provided hash-code function with iAdd as argument.

Parameters:

iAdd: Item to insert

Returns:

If the key already exists, nothing is inserted and 0 is returned else iAdd is inserted in a bucket and 1 is returned.

o KeyLocate

public KeyLocate( iKey)

Returns the item with has a given hash value key.

Parameters:

iKey: Hash value key.

Returns:

The item which has iKey hash table key value, or NULL if not found.

o KeyLocatePosition

public KeyLocatePosition(		`iKey`,
		`oBucket`,
		`oPosition`)

Returns the item with has a given hash value key.

Parameters:

iKey: Hash value key.
oBucket: the bucket of the item
oPosition: The position of this item in the bucket.

Returns:

The item which has iKey hash table key value, or NULL if not found.

o Locate

public Locate( iLocate)

Returns an item from a key corresponding to an another item.

Parameters:

iLocate: We used it's key .

Returns:

The item having a key corresponding to iLocate key's or NULL if not found.

o LocatePosition

public LocatePosition(		`iLocate`,
		`oBucket`,
		`oPosition`)

Returns an item from a key corresponding to an another item.

Parameters:

iLocate: The element to find in the table.
oBucket: The bucket of the returned item
oPosition: The position in the bucket of the returned item

Returns:

The item having a key corresponding to iLocate key's or NULL if not found.

o Next

public Next( iFrom)

Returns the next item given a key in a hash table.
Role:Iterator of the hash table. To start a loop on all items set iFrom to NULL. If the returned value is NULL, you have reached the end of the table.

Parameters:

iFrom: The returned value is the next item of iFrom

Returns:

The next item after iFrom

o Next

public Next(		`ioBucket`,
		`ioPosition`)

Returns the next item given a position in a hash table.
Role:Iterator of the hash table. To start a loop on all items set ioBucket to 1 and ioPosition to 0. If the returned value is NULL, you have reached the end of the table.

Parameters:

ioBucket: The bucket used to find the next item
ioPosition: The position in the ioBucket used to find the next item

Returns:

The next item next to the given position (iBucket, iPosition).

o Remove

public Remove( iRemove)

Removes an item in the hash table.

Parameters:

iRemove: The element to remove

Returns:

The element removed or NULL if not exists

o RemoveAll

public RemoveAll(

)

Removes all elements in the hash table.

o RemovePosition

public RemovePosition(		`iBucket`,
		`iPosition`)

Removes an item in the hash table.

Returns:: The element removed or NULL if not exists

o Retrieve

public Retrieve(		`iBucket`,
		`iPosition`)

Retrieves an item from its Bucket and Position in a hash table.

Parameters:

iBucket: The bucket of the returned item
iPosition: The position in the bucket of the returned item

Returns:

Returns the item having position descibed by the couple of integer (iBucket,iPosition)

o Size

public Size(

)

Returns the count of item in the hash table..

o Unused

public Unused(

)

Returns the count of unused buckets in an hash table.

This object is included in the file: CATHashTable.h
If needed, your Imakefile.mk should include the module: JS0GROUP

System writeClassCharacteristic(); CATHashTable

Constructor and Destructor Index

Method Index

Constructor and Destructor

Methods

System CATHashTable