Data.VCache.Trie

A compact bytestring trie implemented above VCache.

Documentation

data Trie a

A trie data structure with bytesting keys, above VCache.

This trie uses a simple node structure, with a large branching factor (arity 256), and serializing large shared prefixes and the element values into the same node. The root of the trie is simply a `Maybe (VRef node)`, so is efficient for equality comparisons and serialization purposes. The basic Show instance reports only the root reference address.

The trie supports keys of arbitrary size, though very large keys may cause some performance degradation. Similarly, very large values may cause performance degradation since every lookup will load every value in the path.

Instances

Eq (Trie a)

Show (Trie a)

VCacheable a => VCacheable (Trie a)

Typeable (* -> *) Trie

trie_space :: Trie a -> VSpace

empty :: VSpace -> Trie a

Construct Trie with no elements.

singleton :: VCacheable a => VSpace -> ByteString -> a -> Trie a

Construct Trie with one element.

null :: Trie a -> Bool

O(1), test whether trie is empty.

size :: Trie a -> Int

O(n). Compute size of the trie.

lookup :: ByteString -> Trie a -> Maybe a

Lookup an object by key

lookup' :: ByteString -> Trie a -> Maybe a

Lookup an object by key without caching nodes

lookupc :: CacheMode -> ByteString -> Trie a -> Maybe a

Lookup object by key with a specific cache mode.

prefixKeys :: VCacheable a => ByteString -> Trie a -> Trie a

O(1). Add a common prefix to all keys currently in the Trie

lookupPrefix :: VCacheable a => ByteString -> Trie a -> Trie a

Obtain a trie rooted at a given prefix.

This operation may need to allocate a new node.

deletePrefix :: VCacheable a => ByteString -> Trie a -> Trie a

Delete all keys sharing a given prefix.

insert :: VCacheable a => ByteString -> a -> Trie a -> Trie a

Insert a single key,value pair into the trie, replacing any existing value at that location.

delete :: VCacheable a => ByteString -> Trie a -> Trie a

Remove a single key from the trie.

adjust :: VCacheable a => (Maybe a -> Maybe a) -> ByteString -> Trie a -> Trie a

Update an element in the Trie with a given function. Capable of inserts, modifies, and deletes.

insertList :: VCacheable a => [(ByteString, a)] -> Trie a -> Trie a

Insert a list of (key,value) pairs into the trie. At the moment this is just a linear insert, but it may later be replaced by an efficient batch-insert model. If a key appears more than once in this list, the last entry will win.

deleteList :: VCacheable a => [ByteString] -> Trie a -> Trie a

Remove a collection of keys from the trie. At the moment this is just a sequential deletion, but it may later be replaced by a more efficient batch-deletion model.

toList :: Trie a -> [(ByteString, a)]

O(n). Obtain a list of (key,val) pairs, sorted by key.

toListBy :: (ByteString -> a -> b) -> Trie a -> [b]

elems :: Trie a -> [a]

O(n). Obtain list of elements in the trie.

keys :: Trie a -> [ByteString]

O(n). Obtain a sorted list of of keys.

foldr :: (a -> b -> b) -> b -> Trie a -> b

foldr' :: (a -> b -> b) -> b -> Trie a -> b

foldrM :: Monad m => (a -> b -> m b) -> b -> Trie a -> m b

foldrWithKey :: (ByteString -> a -> b -> b) -> b -> Trie a -> b

foldrWithKey' :: (ByteString -> a -> b -> b) -> b -> Trie a -> b

foldrWithKeyM :: Monad m => (ByteString -> a -> b -> m b) -> b -> Trie a -> m b

foldl :: (b -> a -> b) -> b -> Trie a -> b

foldl' :: (b -> a -> b) -> b -> Trie a -> b

foldlM :: Monad m => (b -> a -> m b) -> b -> Trie a -> m b

foldlWithKey :: (b -> ByteString -> a -> b) -> b -> Trie a -> b

foldlWithKey' :: (b -> ByteString -> a -> b) -> b -> Trie a -> b

foldlWithKeyM :: Monad m => (b -> ByteString -> a -> m b) -> b -> Trie a -> m b

map :: VCacheable b => (a -> b) -> Trie a -> Trie b

mapM :: (VCacheable b, Monad m) => (a -> m b) -> Trie a -> m (Trie b)

mapWithKey :: VCacheable b => (ByteString -> a -> b) -> Trie a -> Trie b

mapWithKeyM :: (Monad m, VCacheable b) => (ByteString -> a -> m b) -> Trie a -> m (Trie b)

validate :: Trie a -> Bool

Validate the invariant structure of the Trie. Every node must branch or contain a value.

unsafeTrieAddr :: Trie a -> Word64

Obtain unique address for Trie value. As with VRef addresses, this should be stable while the Trie is reachable, but may change if the value is GC'd and later reconstructed at a new address. Exposed for memoization and similar purposes.