Implementation of LRU (least recently used) timed cache. More...

#include <lru_map.h>

Inheritance diagram for servlet::lru_map< _Key, _Tp, _MT >:

Public Types
typedef linked_map< _Key, _Tp, _MT >	base_type
	Type of base `linked_map`

typedef base_type::key_type	key_type
	Container's key type.

typedef base_type::mapped_type	mapped_type
	Container's mapped type.

typedef base_type::value_type	value_type
	Container's value type: `std::pair<const key_type&, mapped_type>`

typedef base_type::allocator_type	allocator_type
	Container's allocator type.

typedef base_type::reference	reference
	`value_type&`

typedef base_type::const_reference	const_reference
	`const value_type&`

typedef base_type::pointer	pointer
	Pointer to value_type type.

typedef base_type::const_pointer	const_pointer
	Constant pointer to value_type type.

typedef base_type::size_type	size_type
	An unsigned integral type to represent the size of this container.

typedef base_type::difference_type	difference_type
	A signed integral type to represent distance between iterators.

typedef base_type::iterator	iterator
	Bidirectional iterator type.

typedef base_type::const_iterator	const_iterator
	Bidirectional constant iterator type.

typedef base_type::reverse_iterator	reverse_iterator
	Reverse iterator type.

typedef base_type::const_reverse_iterator	const_reverse_iterator
	Constant reverse iterator type.

Public Types inherited from servlet::linked_map< _Key, _Tp, _MT >
typedef _Key	key_type
	Container's key type.

typedef _Tp	mapped_type
	Container's mapped type.

typedef std::pair< const _Key &, _Tp >	value_type
	Container's value type: `std::pair<const key_type&, mapped_type>`

typedef linked_map< _Key, _Tp, _MT >	self_type
	The type of this container. More...

typedef std::list< value_type >	list_type
	List type to maintain the order of elements.

typedef _MT	map_type
	Underlying map type.

typedef map_type::allocator_type	allocator_type
	Container's allocator type.

typedef value_type &	reference
	`value_type&`

typedef const value_type &	const_reference
	`const value_type&`

typedef value_type *	pointer
	Pointer to value_type type.

typedef const value_type *	const_pointer
	Constant pointer to value_type type.

typedef map_type::size_type	size_type
	An unsigned integral type to represent the size of this container.

typedef map_type::difference_type	difference_type
	A signed integral type to represent distance between iterators.

typedef list_type::iterator	iterator
	Bidirectional iterator type.

typedef list_type::const_iterator	const_iterator
	Bidirectional constant iterator type.

typedef list_type::reverse_iterator	reverse_iterator
	Reverse iterator type.

typedef list_type::const_reverse_iterator	const_reverse_iterator
	Constant reverse iterator type.

Public Member Functions
	lru_map (std::size_t timeout_sec)
	Constructs an empty container, with no elements. More...

	lru_map (const lru_map &other)
	Copy constructor. More...

	lru_map (lru_map &&other)
	Move constructor. More...

lru_map &	operator= (const lru_map &other)
	The copy assignment. More...

lru_map &	operator= (lru_map &&other)
	The move assignment. More...

void	set_timeout (std::size_t timeout_sec)
	Sets the timeout after which inactive elements will be purged from the cache. More...

template<typename KeyType >
bool	contains_key (const KeyType &key) const
	Tests whether value with a given key exists in this container. More...

void	clear ()
	Clear content. More...

template<typename KeyType >
optional_ref< const mapped_type >	get (const KeyType &key) const
	Returns `optional_ref` object to a value with a specified type, if that value exists and can be casted to the requested type. More...

template<typename KeyType >
optional_ref< mapped_type >	get (const KeyType &key)
	Returns `optional_ref` object to a value with a specified type, if that value exists and can be casted to the requested type. More...

template<class... Args>
bool	put (key_type &&key, Args &&...args)
	Associates a value of specified type created with a given arguments with the specified key in this map. More...

template<class... Args>
bool	put (const key_type &key, Args &&...args)
	Associates a value of specified type created with a given arguments with the specified key in this map. More...

template<class... Args>
bool	try_put (key_type &&key, Args &&...args)
	Associates a value of specified type created with a given arguments with the specified key in this map. More...

template<class... Args>
bool	try_put (const key_type &key, Args &&...args)
	Associates a value of specified type created with a given arguments with the specified key in this map. More...

template<typename KeyType >
bool	erase (const KeyType &key)
	Erase element. More...

Public Member Functions inherited from servlet::linked_map< _Key, _Tp, _MT >
	linked_map ()=default
	Constructs an empty container, with no elements.

	linked_map (const linked_map &m)=default
	Copy constructor. More...

	linked_map (linked_map &&m)=default
	Move constructor. More...

linked_map &	operator= (const linked_map &m)=default
	The copy assignment. More...

linked_map &	operator= (linked_map &&m)=default
	The move assignment. More...

bool	empty () const noexcept
	Test whether container is empty. More...

size_type	size () const noexcept
	Returns the number of elements in the container. More...

template<typename KeyType >
bool	contains_key (const KeyType &key) const
	Tests whether value with a given key exists in this container. More...

void	clear ()
	Clear content. More...

template<typename KeyType >
optional_ref< const mapped_type >	get (const KeyType &key) const
	Returns `optional_ref` object to a value with a specified type, if that value exists and can be casted to the requested type. More...

template<typename KeyType >
optional_ref< mapped_type >	get (const KeyType &key)
	Returns `optional_ref` object to a value with a specified type, if that value exists and can be casted to the requested type. More...

template<class... Args>
bool	put (key_type &&key, Args &&...args)
	Associates a value of specified type created with a given arguments with the specified key in this map. More...

template<class... Args>
bool	put (const key_type &key, Args &&...args)
	Associates a value of specified type created with a given arguments with the specified key in this map. More...

template<class... Args>
bool	try_put (key_type &&key, Args &&...args)
	Associates a value of specified type created with a given arguments with the specified key in this map. More...

template<class... Args>
bool	try_put (const key_type &key, Args &&...args)
	Associates a value of specified type created with a given arguments with the specified key in this map. More...

template<typename KeyType >
bool	erase (const KeyType &key)
	Erase element. More...

iterator	begin () noexcept
	Returns iterator to beginning of the container. More...

iterator	end () noexcept
	Return iterator to end of the container. More...

const_iterator	begin () const noexcept
	Returns constant iterator to beginning of the container. More...

const_iterator	end () const noexcept
	Return constant iterator to end of the container. More...

const_iterator	cbegin () const noexcept
	Returns constant iterator to beginning of the container. More...

const_iterator	cend () const noexcept
	Return constant iterator to end of the container. More...

reverse_iterator	rbegin () noexcept
	Return reverse iterator to reverse beginning. More...

reverse_iterator	rend () noexcept
	Return reverse iterator to reverse end. More...

const_reverse_iterator	rbegin () const noexcept
	Return constant reverse iterator to reverse beginning. More...

const_reverse_iterator	rend () const noexcept
	Return constant reverse iterator to reverse end. More...

const_reverse_iterator	crbegin () const noexcept
	Return constant reverse iterator to reverse beginning. More...

const_reverse_iterator	crend () const noexcept
	Return constant reverse iterator to reverse end. More...

Protected Member Functions
void	update (value_type &val) const override
	Updates access timestamp of the element. More...

void	purge () override
	Removes all the elements from the cache which has not been accessed for longer than this cache timeout.

Detailed Description

template<typename _Key, typename _Tp, typename _MT>
class servlet::lru_map< _Key, _Tp, _MT >

Implementation of LRU (least recently used) timed cache.

This class keeps track of time when elements were accessed and removes them if the have not been accessed for longer than timeout

This is a synchronized container.

Template Parameters

_Key	type of the key
_Tp	type of the mapped value
_MT	type of the base map for this class to inherit from. Currently it can be either `std::map` or `std::unordered_map`

See Also: linked_map

Constructor & Destructor Documentation

template<typename _Key , typename _Tp , typename _MT >

servlet::lru_map< _Key, _Tp, _MT >::lru_map ( std::size_t timeout_sec )

inline

Constructs an empty container, with no elements.

The timeout argument is specified in seconds. After this number of seconds if element is not accessed it will be removed from this container.

Parameters

timeout_sec Expiration time for elements in this container.

template<typename _Key , typename _Tp , typename _MT >

servlet::lru_map< _Key, _Tp, _MT >::lru_map ( const lru_map< _Key, _Tp, _MT > & other )

inline

Copy constructor.

Constructs a container with a copy of each of the elements in other.

Parameters

Member Function Documentation

template<typename _Key , typename _Tp , typename _MT >

void servlet::lru_map< _Key, _Tp, _MT >::clear ( )

inline

Clear content.

Removes all elements from the container (which are destroyed), leaving the container with a size of 0

template<typename _Key , typename _Tp , typename _MT >

template<typename KeyType >

bool servlet::lru_map< _Key, _Tp, _MT >::contains_key ( const KeyType & key ) const

inline

Tests whether value with a given key exists in this container.

Template Parameters

KeyType a type comparable to type of this map's key (via std::less<>

Parameters

key	Key to test.

Returns: true if a value with a given key exists in this container, false otherwise.

template<typename _Key , typename _Tp , typename _MT >

template<typename KeyType >

bool servlet::lru_map< _Key, _Tp, _MT >::erase ( const KeyType & key )

inline

Erase element.

Removes from the container a single element identified by a given key. Does nothing if the element with a given key is not found.

Template Parameters

KeyType a type comparable to type of this map's key (via std::less<>

Parameters

key	Key of the element to remove.

Returns: true if the element was actually removed, false otherwise.

template<typename _Key , typename _Tp , typename _MT >

template<typename KeyType >

optional_ref<const mapped_type> servlet::lru_map< _Key, _Tp, _MT >::get ( const KeyType & key ) const

inline

Returns optional_ref object to a value with a specified type, if that value exists and can be casted to the requested type.

If the value with a given key doesn't exists empty optional_ref will be returned.

Template Parameters

KeyType a type comparable to type of this map's key (via std::less<>

Parameters

key	Key to be searched for.

Returns: optional_ref to the found value, or empty reference if a value with a given key doesn't exists in this container.

Exceptions

std::bad_any_cast if the value is found, but couldn't be casted to the requested type

template<typename _Key , typename _Tp , typename _MT >

template<typename KeyType >

optional_ref<mapped_type> servlet::lru_map< _Key, _Tp, _MT >::get ( const KeyType & key )

inline

Returns optional_ref object to a value with a specified type, if that value exists and can be casted to the requested type.

If the value with a given key doesn't exists empty optional_ref will be returned.

Template Parameters

KeyType a type comparable to type of this map's key (via std::less<>

Parameters

key	Key to be searched for.

Returns: optional_ref to the found value, or empty reference if a value with a given key doesn't exists in this container.

Exceptions

std::bad_any_cast if the value is found, but couldn't be casted to the requested type

template<typename _Key , typename _Tp , typename _MT >

lru_map& servlet::lru_map< _Key, _Tp, _MT >::operator= ( const lru_map< _Key, _Tp, _MT > & other )

inline

The copy assignment.

Copies all the elements from other into the container (with other preserving its contents)

Parameters

other Cache object to copy from.

Returns: reference to self

template<typename _Key , typename _Tp , typename _MT >

lru_map& servlet::lru_map< _Key, _Tp, _MT >::operator= ( lru_map< _Key, _Tp, _MT > && other )

inline

The move assignment.

Moves the elements of other into the container (other is left in an unspecified but valid state).

Parameters

other Cache object to move from.

Returns: reference to self

template<typename _Key , typename _Tp , typename _MT >

template<class... Args>

bool servlet::lru_map< _Key, _Tp, _MT >::put	(	key_type &&	key,
		Args &&...	args
	)

inline

Associates a value of specified type created with a given arguments with the specified key in this map.

If the map previously contained a mapping for the key, the old value is replaced.

Template Parameters

Args	types of the arguments to be forwarded to new mapped value constructor.

Parameters

key	key with which the specified value is to be associated
args	arguments to create the mapped value

Returns: bool denoting whether the previous value was replaced.

See Also: try_put

template<typename _Key , typename _Tp , typename _MT >

template<class... Args>

bool servlet::lru_map< _Key, _Tp, _MT >::put	(	const key_type &	key,
		Args &&...	args
	)

inline

Associates a value of specified type created with a given arguments with the specified key in this map.

If the map previously contained a mapping for the key, the old value is replaced.

Template Parameters

Args	types of the arguments to be forwarded to new mapped value constructor.

Parameters

key	key with which the specified value is to be associated
args	argument to create the mapped value

Returns: bool denoting whether the previous value was replaced.

See Also: try_put

template<typename _Key , typename _Tp , typename _MT >

void servlet::lru_map< _Key, _Tp, _MT >::set_timeout ( std::size_t timeout_sec )

inline

Sets the timeout after which inactive elements will be purged from the cache.

Parameters

timeout_sec Number of seconds after which inactive element will be removed.

template<typename _Key , typename _Tp , typename _MT >

template<class... Args>

bool servlet::lru_map< _Key, _Tp, _MT >::try_put	(	key_type &&	key,
		Args &&...	args
	)

inline

Associates a value of specified type created with a given arguments with the specified key in this map.

If the map previously contained a mapping for the key, does nothing.

Template Parameters

Args	types of the arguments to be forwarded to new mapped value constructor.

Parameters

key	key with which the specified value is to be associated
args	argument to create the mapped value

Returns: bool denoting whether insertion took place.

See Also: put

template<typename _Key , typename _Tp , typename _MT >

template<class... Args>

bool servlet::lru_map< _Key, _Tp, _MT >::try_put	(	const key_type &	key,
		Args &&...	args
	)

inline

Associates a value of specified type created with a given arguments with the specified key in this map.

If the map previously contained a mapping for the key, does nothing.

Template Parameters

Args	types of the arguments to be forwarded to new mapped value constructor.

Parameters

key	key with which the specified value is to be associated
args	argument to create the mapped value

Returns: bool denoting whether insertion took place.

See Also: put

template<typename _Key , typename _Tp , typename _MT >

void servlet::lru_map< _Key, _Tp, _MT >::update ( value_type & val ) const

inlineoverrideprotectedvirtual

Updates access timestamp of the element.

Parameters

val	Value for which to update the access timestamp.

Reimplemented from servlet::linked_map< _Key, _Tp, _MT >.

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

include/servlet/lib/lru_map.h

Public Types

Public Member Functions

Protected Member Functions

Detailed Description

template<typename _Key, typename _Tp, typename _MT> class servlet::lru_map< _Key, _Tp, _MT >

Constructor & Destructor Documentation

Member Function Documentation

template<typename _Key, typename _Tp, typename _MT>
class servlet::lru_map< _Key, _Tp, _MT >