AbstractHashTable Class Template Reference

Implements an abstract class for defining the core operations of a hash table with chaining. More...

#include <AbstractHashTable.h>

List of all members.

Public Types
typedef size_t	size_type
	The type of the hash indeces.
typedef ListItem< T *> *	hash_element
	The type of a list of hash elements.
Public Methods
	AbstractHashTable (const char *nameBuff="Unnamed")
	Constructor.
	AbstractHashTable (size_type initial_size, const char *nameBuff="Unnamed")
	Constructor.
virtual	~AbstractHashTable ()
	Dummy destructor.
bool	empty () const
	Returns true if the list is empty and false otherwise.
	operator bool () const
	Returns true if the list is empty and false otherwise.
int	size () const
	Returns the number of elements in the hash table.
virtual T *	find (KEY &key) const
	Return the item in the hash table with the given key. More...
virtual T *	first () const
	Return the ``first'' element in the hash table.
virtual void	add (KEY &key)
	Add a key to the hash table.
virtual void	add (KEY &key, T *&item)
	Add a key to the hash table and return the hash table item that contains it.
virtual void	remove (KEY &key, bool &status)
	Remove a hash table item with the given key. More...
virtual void	remove (T *&item, bool &status)
	Remove a hash table item. More...
virtual void	remove (T *&item, KEY &key, bool &status)
	Remove a hash table item and return the item's key. More...
virtual T *	next (T *item)
	Returns the next element in the hash table's list of hash elements.
int	write (ostream &os) const
	Write the hash table to an output stream.
int	read (istream &is)
	Read a hash table from an input stream.
void	clear ()
	Empty the hash table.
void	statistics (ostream &os)
	TODO.
bool &	ignore_duplicates ()
	A flag that can be set to ignore duplicates in the hash table.
void	set_hash_fn (size_type(*hashfn)(const KEY &, size_type))
	Set the hash function used by this HT.
Public Attributes
bool	using_prime_ht
	If true, then the hash table size is prime. Can be set by the user.
size_type(*	curr_hashfn )(const KEY &, size_type)
	A pointer to the current hash function.
Protected Methods
virtual size_type	hash (KEY &key, size_type table_size) const
	Hashes a key with the given table size.
virtual T *	insert (KEY *key)
	Add a key to the tree.
void	insert (T *item, const bool resize_OK=true)
	Add a hash table item to the tree.
virtual void	extract (T *item, bool &status)
	Remove a hash table item. More...
void	resize (const int newsize=-1)
	TODO.
Protected Attributes
LinkedList< T *>	data
	pointers to actual data values.
BasicArray< ListItem< T *> *>	table
	The hash table, which points at list item elements.
BasicArray< int >	bucket_size
	The size of the bucket in the hash table;.
double	max_load
	Resize the table if (# vals)/(table.size()) > max_load.
bool	ignore_duplicates_flag
	Ignore duplicates that are hashed if true.

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Detailed Description

template<class T, class KEY>
class AbstractHashTable< T, KEY >

Implements an abstract class for defining the core operations of a hash table with chaining.

Note: the 'next' method doesn't work if ignore_duplicate==false and there exist duplicates in the hash table. The could probably be fixed by using a iterator construct, though, instead of this method. Consequently, ignore_duplicate==true by default.

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Member Function Documentation

template<class T, class KEY> void AbstractHashTable< T, KEY >::extract (  T *    item, bool &    status )  [protected, virtual]

Remove a hash table item. The status flag is true if the item was found and false otherwise.

template<class T, class KEY> T * AbstractHashTable< T, KEY >::find (  KEY &    key )  const [virtual]

Return the item in the hash table with the given key. Returns null if the table is empty or if the item is not in the tree.

template<class T, class KEY> virtual void AbstractHashTable< T, KEY >::remove (  T *&    item, KEY &    key, bool &    status )  [inline, virtual]

Remove a hash table item and return the item's key. The status flag is true if the item was found and false otherwise.

template<class T, class KEY> virtual void AbstractHashTable< T, KEY >::remove (  T *&    item, bool &    status )  [inline, virtual]

Remove a hash table item. The status flag is true if the item was found and false otherwise.

template<class T, class KEY> virtual void AbstractHashTable< T, KEY >::remove (  KEY &    key, bool &    status )  [inline, virtual]

Remove a hash table item with the given key. The status flag is true if the key was found and false otherwise.

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

• AbstractHashTable.h