Class loon::LRU¶

template <typename K, typename V>

A Least Recently Used ( LRU ) cache with O(1) access and eviction.More...

#include <lru.hpp>

Public Functions¶

Type	Name
	LRU (uint32_t size) Constructs an LRU cache with the specified capacity.
bool	exists (const K & key) const Checks if a key exists in the cache.
std::optional< std::reference_wrapper< V > >	get (const K & key) Retrieves a value from the cache.
void	put (const K & key, const V & value) Inserts or updates a key-value pair in the cache.
void	remove (const K & key) Removes a key-value pair from the cache.
uint32_t	size () const Returns the current number of entries in the cache.

Detailed Description¶

This cache maintains a fixed capacity and automatically evicts the least recently used entries when the capacity is exceeded. Both get() and put() operations update the recency of the accessed key.

Template parameters:

K Key type (must be hashable for std::unordered_map)
V Value type

loon::LRU<std::string, int> cache(100);
cache.put("key", 42);
if (auto val = cache.get("key")) {
    std::cout << val->get() << std::endl;
}

Public Functions Documentation¶

function LRU¶

Constructs an LRU cache with the specified capacity.

inline explicit loon::LRU::LRU (
    uint32_t size
)

Parameters:

size Maximum number of entries the cache can hold.

function exists¶

Checks if a key exists in the cache.

inline bool loon::LRU::exists (
    const K & key
) const

This operation does not affect the recency of the key.

Parameters:

key The key to check.

Returns:

true if the key exists, false otherwise.

function get¶

Retrieves a value from the cache.

inline std::optional< std::reference_wrapper< V > > loon::LRU::get (
    const K & key
)

If the key exists, it is marked as most recently used.

Parameters:

key The key to look up.

Returns:

A reference to the value if found, std::nullopt otherwise.

function put¶

Inserts or updates a key-value pair in the cache.

inline void loon::LRU::put (
    const K & key,
    const V & value
)

If the key already exists, its value is updated and it becomes the most recently used. If the cache is at capacity, the least recently used entry is evicted before inserting the new entry.

Parameters:

key The key to insert or update.
value The value to associate with the key.

function remove¶

Removes a key-value pair from the cache.

inline void loon::LRU::remove (
    const K & key
)

If the key does not exist, this operation has no effect.

Parameters:

key The key to remove.

function size¶

Returns the current number of entries in the cache.

inline uint32_t loon::LRU::size () const

Returns:

The number of cached entries.

The documentation for this class was generated from the following file include/loon/lru.hpp