expiring-cache-map- General purpose simple caching.

Copyright(c) 2014 Edward L. Blake
MaintainerEdward L. Blake <edwardlblake@gmail.com>
Safe HaskellSafe






data CacheSettings Source #



A cache that maintains a key access history list to perform removals of least recently used entries. Once the key-value map reaches removalsize keys, then a list of keys to keep in the map is determined which is no larger than mapsize size. Entries are removed only on insertion of a new entry in the key-value map.

Key access history entries are prepended to the head of the LRU list, if an existing entry for the key appears close to the head of the list it is moved to the head of the list, instead of growing the list. When the LRU list reaches compactlistsize items, it is compacted by removing duplicate keys, by keeping only the most recent accumulator value for that key.

Cache encapsulation

data ECM a b s m k v Source #

The type that encapsulates a cache map.

data CacheState s m k v Source #

The cache state.


type TimeUnits = Int Source #

Integer involved in the time units used to determine when an item expires. The time units used can be any arbitrary integer time representation, such as seconds or milliseconds for examples. They can also be deterministic time steps in a sequencing monad.

type ECMMapSize = Int Source #

Integer involved in the size of a key-value map.

type ECMULength = Int Source #

Integer involved in the length of the usage history list.

type ECMIncr = Word32 Source #

Unsigned integer (Word32) involved in the cache state incrementing accumulator.

Types for state function

type ECMNewState a b s m k v = CacheState s m k v -> a (b (CacheState s m k v)) Source #

type ECMEnterState a b s m k v = b (CacheState s m k v) -> (CacheState s m k v -> a (CacheState s m k v, v)) -> a v Source #

type ECMReadState a b s m k v = b (CacheState s m k v) -> a (CacheState s m k v) Source #