Template cache with an LRU removal policy. More...

#include <lru_cache.h>

Public Types
typedef std::list< std::pair < Key, Data > >	List
	Main cache storage typedef.

typedef List::iterator	List_Iter
	Main cache iterator.

typedef List::const_iterator	List_cIter
	Main cache iterator (const)

typedef std::vector< Key >	Key_List
	List of keys.

typedef Key_List::iterator	Key_List_Iter
	Main cache iterator.

typedef Key_List::const_iterator	Key_List_cIter
	Main cache iterator (const)

typedef std::map< Key, List_Iter >	Map
	Index typedef.

typedef std::pair< Key, List_Iter >	Pair
	Pair of Map elements.

typedef Map::iterator	Map_Iter
	Index iterator.

typedef Map::const_iterator	Map_cIter
	Index iterator (const)

Public Member Functions
	LRUCache (const unsigned long Size)
	Creates a cache that holds at most Size worth of elements. More...

	LRUCache (const LRUCache &that)

LRUCache &	operator= (const LRUCache &that)

	~LRUCache ()
	Destructor - cleans up both index and storage.

unsigned long	size (void) const
	Gets the current abstract size of the cache. More...

unsigned long	max_size (void) const
	Gets the maximum sbstract size of the cache. More...

void	clear (void)
	Clears all storage and indices.

bool	exists (const Key &key) const
	Checks for the existance of a key in the cache. More...

void	remove (const Key &key)
	Removes a key-data pair from the cache. More...

void	touch (const Key &key)
	Touches a key in the Cache and makes it the most recently used. More...

Data *	fetch_ptr (const Key &key, bool touch_data=true)
	Fetches a pointer to cache data. More...

Data	fetch (const Key &key, bool touch_data=true)
	Fetches a copy of cached data. More...

bool	fetch (const Key &key, Data &data, bool touch_data=true)
	Fetches a pointer to cache data. More...

void	insert (const Key &key, const Data &data)
	Inserts a key-data pair into the cache and removes entries if neccessary. More...

void	info ()

const Key_List	get_all_keys (void)
	Get a list of keys. More...

Detailed Description

template<class Key, class Data, class Sizefn = Countfn< Data >>
class LRUCache< Key, Data, Sizefn >

Template cache with an LRU removal policy.

: This template creats a simple collection of key-value pairs that grows until the size specified at construction is reached and then begins discard the Least Recently Used element on each insertion.

Constructor & Destructor Documentation

template<class Key, class Data, class Sizefn = Countfn< Data >>

LRUCache< Key, Data, Sizefn >::LRUCache ( const unsigned long Size )

inline

Creates a cache that holds at most Size worth of elements.

Parameters

Size	maximum size of cache

Member Function Documentation

template<class Key, class Data, class Sizefn = Countfn< Data >>

bool LRUCache< Key, Data, Sizefn >::exists ( const Key & key ) const

inline

Checks for the existance of a key in the cache.

Parameters

key	to check for

Returns: bool indicating whether or not the key was found.

template<class Key, class Data, class Sizefn = Countfn< Data >>

Data LRUCache< Key, Data, Sizefn >::fetch	(	const Key &	key,
		bool	touch_data = `true`
	)

inline

Fetches a copy of cached data.

Parameters

key	to fetch data for
touch_data	whether or not to touch the data

Returns: copy of the data or an empty Data object if not found

template<class Key, class Data, class Sizefn = Countfn< Data >>

bool LRUCache< Key, Data, Sizefn >::fetch	(	const Key &	key,
		Data &	data,
		bool	touch_data = `true`
	)

inline

Fetches a pointer to cache data.

Parameters

key	to fetch data for
data	to fetch data into
touch_data	whether or not to touch the data

Returns: whether or not data was filled in

template<class Key, class Data, class Sizefn = Countfn< Data >>

Data* LRUCache< Key, Data, Sizefn >::fetch_ptr	(	const Key &	key,
		bool	touch_data = `true`
	)

inline

Fetches a pointer to cache data.

Parameters

key	to fetch data for
touch	whether or not to touch the data

Returns: pointer to data or NULL on error

template<class Key, class Data, class Sizefn = Countfn< Data >>

const Key_List LRUCache< Key, Data, Sizefn >::get_all_keys ( void )

inline

Get a list of keys.

Returns: list of the current keys.

template<class Key, class Data, class Sizefn = Countfn< Data >>

void LRUCache< Key, Data, Sizefn >::insert	(	const Key &	key,
		const Data &	data
	)

inline

Inserts a key-data pair into the cache and removes entries if neccessary.

Parameters

key	object key for insertion
data	object data for insertion

Note: This function checks key existance and touches the key if it already exists.

template<class Key, class Data, class Sizefn = Countfn< Data >>

unsigned long LRUCache< Key, Data, Sizefn >::max_size ( void ) const

inline

Gets the maximum sbstract size of the cache.

Returns: maximum size

template<class Key, class Data, class Sizefn = Countfn< Data >>

void LRUCache< Key, Data, Sizefn >::remove ( const Key & key )

inline

Removes a key-data pair from the cache.

Parameters

key	to be removed

template<class Key, class Data, class Sizefn = Countfn< Data >>

unsigned long LRUCache< Key, Data, Sizefn >::size ( void ) const

inline

Gets the current abstract size of the cache.

Returns: current size

template<class Key, class Data, class Sizefn = Countfn< Data >>

void LRUCache< Key, Data, Sizefn >::touch ( const Key & key )

inline

Touches a key in the Cache and makes it the most recently used.

Parameters

key	to be touched

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

/net/opt/univers/ubp-i-15.3-centos7-x64.urij/include/hds_db/qsql/lru_cache.h

Public Types

Public Member Functions

Detailed Description

template<class Key, class Data, class Sizefn = Countfn< Data >> class LRUCache< Key, Data, Sizefn >

Constructor & Destructor Documentation

Member Function Documentation

template<class Key, class Data, class Sizefn = Countfn< Data >>
class LRUCache< Key, Data, Sizefn >