thash-0.1 Contents Index

Data.THash Portability non-portable (requires STM) Stability experimental Maintainer Edward Kmett <ekmett@gmail.com>

Description

A simple STM — unavailable from the original server (HTTP 404) based transactional linear hash table based on Witold 1980. This wraps a Data.THash.THT in an simple container. It may be more appropriate to use the underlying THT — unavailable from the original server (HTTP 404) structure directly if you are nesting these. The performance hit hasn't yet been measured.

Synopsis

data THash k v new :: (k -> Int) -> STM (THash k v) newH :: Hashable k => STM (THash k v) fromList :: Eq k => (k -> Int) -> [(k, v)] -> STM (THash k v) insert :: Eq k => THash k v -> k -> v -> STM Bool update :: Eq k => THash k v -> k -> v -> STM () modify :: Eq k => THash k v -> k -> (Maybe v -> v) -> STM () delete :: Eq k => THash k v -> k -> STM Bool lookup :: Eq k => THash k v -> k -> STM (Maybe v) mapH :: ((k, v) -> r) -> THash k v -> STM [r] each :: THash k v -> STM [(k, v)] keys :: THash k v -> STM [k] values :: THash k v -> STM [v] hashInt :: Int -> Int

Documentation

data THash k v

A hash with keys of type k to values of type v

new :: (k -> Int) -> STM (THash k v)

Build an empty hash table

newH :: Hashable k => STM (THash k v)

Build an empty hash table using the default hash function for the key type.

fromList :: Eq k => (k -> Int) -> [(k, v)] -> STM (THash k v)

Build a hash table from a list of (key,value) pairs

insert :: Eq k => THash k v -> k -> v -> STM Bool

Insert a value into the hash table. If a value with the key is present then nothing is changed and False is returned.

update :: Eq k => THash k v -> k -> v -> STM ()

Insert a value into the hash table, replacing any value with the same key that is present.

modify :: Eq k => THash k v -> k -> (Maybe v -> v) -> STM ()

Update a value in the hash table using the supplied function.

delete :: Eq k => THash k v -> k -> STM Bool

Remove a value from the hash table. Returns True to indicate success.

lookup :: Eq k => THash k v -> k -> STM (Maybe v)

Lookup a value in the hash table.

mapH :: ((k, v) -> r) -> THash k v -> STM [r]

Map a function over all (key,value) functions in the hash table.

each :: THash k v -> STM [(k, v)]

each = mapH id and returns all (key,value) pairs in the hash.

keys :: THash k v -> STM [k]

each = mapH fst and returns all keys in the hash.

values :: THash k v -> STM [v]

each = mapH snd and returns all values present in the hash.

hashInt :: Int -> Int

Thomas Wang's 32 bit mix function; more effective than a prime modulus for declustering a linear hash, but not good against an adversary, since its easily reversed.

Produced by Haddock version 0.7