lrucache

stdlib::rss::lrucache

A generic least-recently-used cache implemented in pure RustScript.

Import

use stdlib::rss::lrucache;

Data types

Type	Description
`LruCacheState`	Opaque cache state passed to and returned by cache operations.
`LruPeekResult`	Result of a non-promoting cache lookup.
`LruGetResult`	Result of a promoting cache lookup, including the updated cache state.
`LruEntryReport`	Optional oldest or newest cache entry.
`LruEntryRow`	Key-value row returned by `entries`.

Data type details

`LruCacheState`

struct LruCacheState<K, V> {
    capacity: int,
    size: int,
    next_id: int,
    head: int,
    tail: int,
    lookup: map<int>,
    nodes: map<LruNode<K, V>>
}

Opaque cache state passed to and returned by cache operations.

`LruPeekResult`

struct LruPeekResult<V> {
    found: bool,
    value: V
}

Result of a non-promoting cache lookup.

`LruGetResult`

struct LruGetResult<K, V> {
    cache: LruCacheState<K, V>,
    found: bool,
    value: V
}

Result of a promoting cache lookup, including the updated cache state.

`LruEntryReport`

struct LruEntryReport<K, V> {
    found: bool,
    key: K,
    value: V
}

Optional oldest or newest cache entry.

`LruEntryRow`

struct LruEntryRow<K, V> {
    key: K,
    value: V
}

Key-value row returned by entries.

Functions

Function	Description
`new`	Creates an LRU cache with the given capacity.
`capacity`	Returns the cache capacity.
`len`	Returns the number of cached entries.
`is_empty`	Returns whether the cache is empty.
`has`	Returns whether the cache contains a key.
`peek`	Returns the cached value without updating recency.
`get`	Returns the cached value and promotes it to the most recently used position.
`put`	Inserts or updates a cache entry and returns the next cache state.
`touch`	Promotes a key to the most recently used position if it exists.
`remove`	Removes a cache entry by key.
`clear`	Removes all entries from the cache.
`keys`	Returns cache keys from oldest to newest.
`values`	Returns cache values from oldest to newest.
`entries`	Returns cache entries from oldest to newest.
`oldest`	Returns the oldest cache entry report.
`newest`	Returns the newest cache entry report.

Function details

`new`

pub fn new<K, V>(raw_capacity: int) -> LruCacheState<K, V>

Creates an LRU cache with the given capacity.

`capacity`

pub fn capacity<K, V>(cache: LruCacheState<K, V>) -> int

Returns the cache capacity.

`len`

pub fn len<K, V>(cache: LruCacheState<K, V>) -> int

Returns the number of cached entries.

`is_empty`

pub fn is_empty<K, V>(cache: LruCacheState<K, V>) -> bool

Returns whether the cache is empty.

`has`

pub fn has<K, V>(cache: LruCacheState<K, V>, key: K) -> bool

Returns whether the cache contains a key.

`peek`

pub fn peek<K, V>(cache: LruCacheState<K, V>, key: K) -> LruPeekResult<V>

Returns the cached value without updating recency.

`get`

pub fn get<K, V>(cache: LruCacheState<K, V>, key: K) -> LruGetResult<K, V>

Returns the cached value and promotes it to the most recently used position.

`put`

pub fn put<K, V>(cache: LruCacheState<K, V>, key: K, value: V) -> LruCacheState<K, V>

Inserts or updates a cache entry and returns the next cache state.

`touch`

pub fn touch<K, V>(cache: LruCacheState<K, V>, key: K) -> LruCacheState<K, V>

Promotes a key to the most recently used position if it exists.

`remove`

pub fn remove<K, V>(cache: LruCacheState<K, V>, key: K) -> LruCacheState<K, V>

Removes a cache entry by key.

`clear`

pub fn clear<K, V>(cache: LruCacheState<K, V>) -> LruCacheState<K, V>

Removes all entries from the cache.

`keys`

pub fn keys<K, V>(cache: LruCacheState<K, V>) -> [K]

Returns cache keys from oldest to newest.

`values`

pub fn values<K, V>(cache: LruCacheState<K, V>) -> [V]

Returns cache values from oldest to newest.

`entries`

pub fn entries<K, V>(cache: LruCacheState<K, V>) -> [LruEntryRow<K, V>]

Returns cache entries from oldest to newest.

`oldest`

pub fn oldest<K, V>(cache: LruCacheState<K, V>) -> LruEntryReport<K, V>

Returns the oldest cache entry report.

`newest`

pub fn newest<K, V>(cache: LruCacheState<K, V>) -> LruEntryReport<K, V>

Returns the newest cache entry report.