caches::fixed_sized_cache< Key, Value, Policy, HashMap > Class Template Reference

Fixed sized cache that can be used with different policy types (e.g. LRU, FIFO, LFU) More...

#include <cache.hpp>

Public Types
using	map_type = HashMap
using	value_type = typename map_type::mapped_type
using	iterator = typename map_type::iterator
using	const_iterator = typename map_type::const_iterator
using	operation_guard = typename std::lock_guard< std::mutex >
using	on_erase_cb = typename std::function< void(const Key &key, const value_type &value)>

Public Member Functions
	fixed_sized_cache (size_t max_size, const Policy< Key > policy=Policy< Key >{}, on_erase_cb on_erase=[](const Key &, const value_type &) {})
	Fixed sized cache constructor.
void	Put (const Key &key, const Value &value) noexcept
	Put element into the cache.
std::pair< value_type, bool >	TryGet (const Key &key) const noexcept
	Try to get an element by the given key from the cache.
value_type	Get (const Key &key) const
	Get element from the cache if present.
bool	Cached (const Key &key) const noexcept
	Check whether the given key is presented in the cache.
std::size_t	Size () const
	Get number of elements in cache.
bool	Remove (const Key &key)

Protected Member Functions
void	Clear ()
const_iterator	begin () const noexcept
const_iterator	end () const noexcept
void	Insert (const Key &key, const Value &value)
void	Erase (const_iterator elem)
void	Erase (const Key &key)
void	Update (const Key &key, const Value &value)
const_iterator	FindElem (const Key &key) const
std::pair< const_iterator, bool >	GetInternal (const Key &key) const noexcept

Detailed Description

template<typename Key, typename Value, template< typename > class Policy = NoCachePolicy, typename HashMap = std::unordered_map<Key, WrappedValue<Value>>>
class caches::fixed_sized_cache< Key, Value, Policy, HashMap >

Fixed sized cache that can be used with different policy types (e.g. LRU, FIFO, LFU)

Template Parameters

Key	Type of a key (should be hashable)
Value	Type of a value stored in the cache
Policy	Type of a policy to be used with the cache
HashMap	Type of a hashmap to use for cache operations. Should have std::unordered_map compatible interface

Constructor & Destructor Documentation

fixed_sized_cache()

template<typename Key , typename Value , template< typename > class Policy = NoCachePolicy, typename HashMap = std::unordered_map<Key, WrappedValue<Value>>>

caches::fixed_sized_cache< Key, Value, Policy, HashMap >::fixed_sized_cache ( size_t  max_size, const Policy< Key >  policy = Policy<Key>{}, on_erase_cb  on_erase = [](const Key &, const value_type &) {}  )

inlineexplicit

Fixed sized cache constructor.

Exceptions

std::invalid_argument

Parameters

[in]	max_size	Maximum size of the cache
[in]	policy	Cache policy to use
[in]	on_erase	on_erase_cb function to be called when cache's element get erased

Member Function Documentation

Cached()

template<typename Key , typename Value , template< typename > class Policy = NoCachePolicy, typename HashMap = std::unordered_map<Key, WrappedValue<Value>>>

bool caches::fixed_sized_cache< Key, Value, Policy, HashMap >::Cached ( const Key &  key ) const

inlinenoexcept

Check whether the given key is presented in the cache.

Parameters

[in]

key

Element key to check

Return values

true	Element is presented in the case
false	Element is not presented in the case

Get()

template<typename Key , typename Value , template< typename > class Policy = NoCachePolicy, typename HashMap = std::unordered_map<Key, WrappedValue<Value>>>

value_type caches::fixed_sized_cache< Key, Value, Policy, HashMap >::Get ( const Key &  key ) const

inline

Get element from the cache if present.

Warning

This method will change in the future with an optional class capabilities to avoid throwing exceptions

Exceptions

std::range_error

Parameters

[in]

key

Get element by key

Returns

Reference to the value stored by the specified key in the cache

Put()

template<typename Key , typename Value , template< typename > class Policy = NoCachePolicy, typename HashMap = std::unordered_map<Key, WrappedValue<Value>>>

void caches::fixed_sized_cache< Key, Value, Policy, HashMap >::Put ( const Key &  key, const Value &  value  )

inlinenoexcept

Put element into the cache.

Parameters

[in]	key	Key value to use
[in]	value	Value to assign to the given key

Remove()

template<typename Key , typename Value , template< typename > class Policy = NoCachePolicy, typename HashMap = std::unordered_map<Key, WrappedValue<Value>>>

bool caches::fixed_sized_cache< Key, Value, Policy, HashMap >::Remove ( const Key &  key )

inline

Remove an element specified by key

Parameters

[in]

key

Key parameter

Return values

true	if an element specified by key was found and deleted
false	if an element is not present in a cache

Size()

template<typename Key , typename Value , template< typename > class Policy = NoCachePolicy, typename HashMap = std::unordered_map<Key, WrappedValue<Value>>>

std::size_t caches::fixed_sized_cache< Key, Value, Policy, HashMap >::Size ( ) const

inline

Get number of elements in cache.

Returns

Number of elements currently stored in the cache

TryGet()

template<typename Key , typename Value , template< typename > class Policy = NoCachePolicy, typename HashMap = std::unordered_map<Key, WrappedValue<Value>>>

std::pair< value_type, bool > caches::fixed_sized_cache< Key, Value, Policy, HashMap >::TryGet ( const Key &  key ) const

inlinenoexcept

Try to get an element by the given key from the cache.

Parameters

[in]

key

Get element by key

Returns

Pair of iterator that points to the element and boolean value that shows whether get operation has been successful or not. If pair's boolean value is false, the element is not presented in the cache. If pair's boolean value is true, returned iterator can be used to get access to the element

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

• cache.hpp