| Safe Haskell | Safe-Inferred |
|---|---|
| Language | Haskell98 |
Data.Cache.LRU
Description
Implements an LRU cache.
This module provides a pure LRU cache based on a doubly-linked list
through a Data.Map structure. This gives O(log n) operations on
insert, lookup, delete, and pop, and O(n * log n) for toList.
The interface this module provides is opaque. If further control is desired, the Data.Cache.LRU.Internal module can be used.
- data LRU key val
- newLRU :: Ord key => Maybe Integer -> LRU key val
- fromList :: Ord key => Maybe Integer -> [(key, val)] -> LRU key val
- toList :: Ord key => LRU key val -> [(key, val)]
- maxSize :: LRU key val -> Maybe Integer
- insert :: Ord key => key -> val -> LRU key val -> LRU key val
- lookup :: Ord key => key -> LRU key val -> (LRU key val, Maybe val)
- delete :: Ord key => key -> LRU key val -> (LRU key val, Maybe val)
- pop :: Ord key => LRU key val -> (LRU key val, Maybe (key, val))
- size :: LRU key val -> Int
Documentation
Stores the information that makes up an LRU cache
Make an LRU. If a size limit is specified, the LRU is guaranteed to not grow above the specified number of entries.
Arguments
| :: Ord key | |
| => Maybe Integer | the optional maximum size of the LRU |
| -> [(key, val)] | |
| -> LRU key val |
Build a new LRU from the given maximum size and list of contents, in order from most recently accessed to least recently accessed.
toList :: Ord key => LRU key val -> [(key, val)] Source
Retrieve a list view of an LRU. The items are returned in order from most recently accessed to least recently accessed.
insert :: Ord key => key -> val -> LRU key val -> LRU key val Source
Add an item to an LRU. If the key was already present in the LRU, the value is changed to the new value passed in. The item added is marked as the most recently accessed item in the LRU returned.
If this would cause the LRU to exceed its maximum size, the least recently used item is dropped from the cache.
lookup :: Ord key => key -> LRU key val -> (LRU key val, Maybe val) Source
Look up an item in an LRU. If it was present, it is marked as the most recently accesed in the returned LRU.
delete :: Ord key => key -> LRU key val -> (LRU key val, Maybe val) Source
Remove an item from an LRU. Returns the new LRU, and the value removed if the key was present.