{-# OPTIONS -XBangPatterns #-}
-- ----------------------------------------------------------------------------
{- |
Module : Data.StringMap.Base
Copyright : Copyright (C) 2009-2012 Uwe Schmidt
License : MIT
Maintainer : Uwe Schmidt (uwe@fh-wedel.de)
Stability : experimental
Portability: not portable
An efficient implementation of maps from strings to arbitrary values.
Values can associated with an arbitrary byte key. Searching for keys is very fast, but
the prefix tree probably consumes more memory than "Data.Map". The main differences are the special
'prefixFind' functions, which can be used to perform prefix queries. The interface is
heavily borrowed from "Data.Map" and "Data.IntMap".
Most other function names clash with "Prelude" names, therefore this module is usually
imported @qualified@, e.g.
> import Data.StringMap (StringMap)
> import qualified Data.StringMap as T
Many functions have a worst-case complexity of /O(min(n,L))/. This means that the operation
can become linear with the number of elements with a maximum of /L/, the length of the
key (the number of bytes in the list). The functions for searching a prefix have a worst-case
complexity of /O(max(L,R))/. This means that the operation can become linear with
/R/, the number of elements found for the prefix, with a minimum of /L/.
The module exports include the internal data types, their constructors and access
functions for ultimate flexibility. Derived modules should not export these
(as shown in "Holumbus.Data.StrMap") to provide only a restricted interface.
-}
-- ----------------------------------------------------------------------------
module Data.StringMap.Base
(
-- * Map type
StringMap (Empty, Val, Branch)-- (..) I don't think we should export the constructors.
, Key
-- * Operators
, (!)
-- * Query
, value
, valueWithDefault
, null
, size
, member
, lookup
, findWithDefault
, prefixFind
, prefixFindWithKey
, prefixFindWithKeyBF
-- * Construction
, empty
, singleton
-- ** Insertion
, insert
, insertWith
, insertWithKey
-- ** Delete\/Update
, delete
, update
, updateWithKey
-- * Combine
-- ** Union
, union
, unionWith
, unionWithKey
-- ** Difference
, difference
, differenceWith
, differenceWithKey
-- * Traversal
-- ** Map
, map
, mapWithKey
, mapM
, mapWithKeyM
-- * Folds
, fold
, foldWithKey
-- * Conversion
, keys
, elems
-- ** Lists
, fromList
, toList
, toListBF
-- ** Maps
, fromMap
, toMap
-- * Debugging
, space
, keyChars
-- Internal
, cutPx'
, cutAllPx'
, branch
, val
, norm
, normError
)
where
import Prelude hiding ( succ, lookup, map, mapM, null )
import Control.Arrow
import Control.DeepSeq
import qualified Data.Foldable
import Data.Binary
import qualified Data.List as L
import qualified Data.Map as M
import Data.Maybe
import Data.StringMap.Types
import Data.StringMap.StringSet
data StringMap v = Empty
| Val { value' :: v
, tree :: ! (StringMap v)
}
| Branch { sym :: {-# UNPACK #-}
! Sym
, child :: ! (StringMap v)
, next :: ! (StringMap v)
}
-- the space optimisation nodes, these
-- will be normalized during access into
-- the three constructors Empty, Val and Branch
| Leaf { value' :: v -- a value at a leaf of the tree
}
| Last { sym :: {-# UNPACK #-}
! Sym -- the last entry in a branch list
, child :: ! (StringMap v) -- or no branch but a single child
}
| LsSeq { syms :: ! Key1 -- a sequence of single childs
, child :: ! (StringMap v) -- in a last node
}
| BrSeq { syms :: ! Key1 -- a sequence of single childs
, child :: ! (StringMap v) -- in a branch node
, next :: ! (StringMap v)
}
| LsSeL { syms :: ! Key1 -- a sequence of single childs
, value' :: v -- with a leaf
}
| BrSeL { syms :: ! Key1 -- a sequence of single childs
, value' :: v -- with a leaf in a branch node
, next :: ! (StringMap v)
}
| BrVal { sym :: {-# UNPACK #-}
! Sym -- a branch with a single char
, value' :: v -- and a value
, next :: ! (StringMap v)
}
| LsVal { sym :: {-# UNPACK #-}
! Sym -- a last node with a single char
, value' :: v -- and a value
}
deriving (Show, Eq, Ord)
-- | strict list of chars with unpacked fields
--
-- for internal use in prefix tree to optimize space efficiency
data Key1 = Nil
| Cons {-# UNPACK #-}
! Sym
! Key1
deriving (Eq, Ord)
instance Show Key1 where
show k = show (toKey k)
(.++.) :: Key1 -> Key1 -> Key1
Nil .++. k2 = k2
(Cons k k1) .++. k2 = Cons k (k1 .++. k2)
toKey :: Key1 -> Key
toKey Nil = []
toKey (Cons c k1) = c : toKey k1
fromKey :: Key -> Key1
fromKey k1 = foldr Cons Nil k1
length1 :: Key1 -> Int
length1 = length . toKey
-- ----------------------------------------
-- smart constructors
empty :: StringMap v
empty = Empty
{-# INLINE empty #-}
val :: v -> StringMap v -> StringMap v
val v Empty = Leaf v
val v t = Val v t
{-# INLINE val #-}
branch :: Sym -> StringMap v -> StringMap v -> StringMap v
branch !_k Empty n = n
branch !k (Leaf v ) Empty = LsVal k v
branch !k (LsVal k1 v) Empty = LsSeL (Cons k (Cons k1 Nil)) v
branch !k (LsSeL ks v) Empty = LsSeL (Cons k ks) v
branch !k (Last k1 c) Empty = lsseq (Cons k (Cons k1 Nil)) c
branch !k (LsSeq ks c) Empty = lsseq (Cons k ks) c
branch !k c Empty = Last k c
branch !k (Leaf v ) n = BrVal k v n
branch !k (LsVal k1 v) n = BrSeL (Cons k (Cons k1 Nil)) v n
branch !k (LsSeL ks v) n = BrSeL (Cons k ks) v n
branch !k (Last k1 c) n = brseq (Cons k (Cons k1 Nil)) c n
branch !k (LsSeq ks c) n = brseq (Cons k ks) c n
branch !k c n = Branch k c n
lsseq :: Key1 -> StringMap v -> StringMap v
lsseq !k (Leaf v) = LsSeL k v
lsseq !k c = LsSeq k c
{-# INLINE lsseq #-}
brseq :: Key1 -> StringMap v -> StringMap v -> StringMap v
brseq !k (Leaf v) n = BrSeL k v n
brseq !k c n = BrSeq k c n
{-# INLINE brseq #-}
siseq :: Key1 -> StringMap v -> StringMap v
siseq Nil c = c
siseq (Cons k1 Nil) c = Last k1 c
siseq k c = LsSeq k c
{-# INLINE siseq #-}
-- smart selectors
norm :: StringMap v -> StringMap v
norm (Leaf v) = Val v empty
norm (Last k c) = Branch k c empty
norm (LsSeq (Cons k Nil) c) = Branch k c empty
norm (LsSeq (Cons k ks ) c) = Branch k (siseq ks c) empty
norm (BrSeq (Cons k Nil) c n) = Branch k c n
norm (BrSeq (Cons k ks ) c n) = Branch k (siseq ks c) n
norm (LsSeL ks v) = norm (LsSeq ks (val v empty))
norm (BrSeL ks v n) = norm (BrSeq ks (val v empty) n)
norm (LsVal k v) = norm (LsSeq (Cons k Nil) (val v empty))
norm (BrVal k v n) = norm (BrSeq (Cons k Nil) (val v empty) n)
norm t = t
-- ----------------------------------------
deepNorm :: StringMap v -> StringMap v
deepNorm t0
= case norm t0 of
Empty -> Empty
Val v t -> Val v (deepNorm t)
Branch c s n -> Branch c (deepNorm s) (deepNorm n)
_ -> normError "deepNorm"
-- ----------------------------------------
normError :: String -> a
normError f = error (f ++ ": pattern match error, prefix tree not normalized")
-- ----------------------------------------
-- | /O(1)/ Is the map empty?
null :: StringMap a -> Bool
null Empty = True
null _ = False
{-# INLINE null #-}
-- | /O(1)/ Create a map with a single element.
singleton :: Key -> a -> StringMap a
singleton k v = foldr (\ c r -> branch c r empty) (val v empty) $ k -- siseq k (val v empty)
{-# INLINE singleton #-}
-- | /O(1)/ Extract the value of a node (if there is one)
-- TODO: INTERNAL
value :: Monad m => StringMap a -> m a
value t = case norm t of
Val v _ -> return v
_ -> fail "StringMap.value: no value at this node"
{-# INLINE value #-}
-- | /O(1)/ Extract the value of a node or return a default value if no value exists.
valueWithDefault :: a -> StringMap a -> a
valueWithDefault d t = fromMaybe d . value $ t
-- | /O(1)/ Extract the successors of a node
succ :: StringMap a -> StringMap a
succ t = case norm t of
Val _ t' -> succ t'
t' -> t'
{-# INLINE succ #-}
-- ----------------------------------------
-- | /O(min(n,L))/ Find the value associated with a key. The function will @return@ the result in
-- the monad or @fail@ in it if the key isn't in the map.
lookup :: Monad m => Key -> StringMap a -> m a
lookup k t = case lookup' k t of
Just v -> return v
Nothing -> fail "StringMap.lookup: Key not found"
{-# INLINE lookup #-}
-- | /O(min(n,L))/ Find the value associated with a key. The function will @return@ the result in
-- the monad or @fail@ in it if the key isn't in the map.
findWithDefault :: a -> Key -> StringMap a -> a
findWithDefault v0 k = fromMaybe v0 . lookup' k
{-# INLINE findWithDefault #-}
-- | /O(min(n,L))/ Is the key a member of the map?
member :: Key -> StringMap a -> Bool
member k = isJust . lookup k
{-# INLINE member #-}
-- | /O(min(n,L))/ Find the value at a key. Calls error when the element can not be found.
(!) :: StringMap a -> Key -> a
(!) = flip $ findWithDefault (error "StringMap.! : element not in the map")
-- | /O(min(n,L))/ Insert a new key and value into the map. If the key is already present in
-- the map, the associated value will be replaced with the new value.
insert :: Key -> a -> StringMap a -> StringMap a
insert = insertWith const
{-# INLINE insert #-}
-- | /O(min(n,L))/ Insert with a combining function. If the key is already present in the map,
-- the value of @f new_value old_value@ will be inserted.
insertWith :: (a -> a -> a) -> Key -> a -> StringMap a -> StringMap a
insertWith f = flip $ insert' f
{-# INLINE insertWith #-}
-- | /O(min(n,L))/ Insert with a combining function. If the key is already present in the map,
-- the value of @f key new_value old_value@ will be inserted.
insertWithKey :: (Key -> a -> a -> a) -> Key -> a -> StringMap a -> StringMap a
insertWithKey f k = insertWith (f k) k
{-# INLINE insertWithKey #-}
-- | /O(min(n,L))/ Updates a value at a given key (if that key is in the trie) or deletes the
-- element if the result of the updating function is 'Nothing'. If the key is not found, the trie
-- is returned unchanged.
update :: (a -> Maybe a) -> Key -> StringMap a -> StringMap a
update = update'
{-# INLINE update #-}
-- | /O(min(n,L))/ Updates a value at a given key (if that key is in the trie) or deletes the
-- element if the result of the updating function is 'Nothing'. If the key is not found, the trie
-- is returned unchanged.
updateWithKey :: (Key -> a -> Maybe a) -> Key -> StringMap a -> StringMap a
updateWithKey f k = update' (f k) k
{-# INLINE updateWithKey #-}
-- | /O(min(n,L))/ Delete an element from the map. If no element exists for the key, the map
-- remains unchanged.
delete :: Key -> StringMap a -> StringMap a
delete = update' (const Nothing)
{-# INLINE delete #-}
-- ----------------------------------------
lookupPx' :: Key -> StringMap a -> StringMap a
lookupPx' k0 = look k0 . norm
where
look [] t = t
look k@(c : k1) (Branch c' s' n')
| c < c' = empty
| c == c' = lookupPx' k1 s'
| otherwise = lookupPx' k n'
look _ Empty = empty
look k (Val _v' t') = lookupPx' k t'
look _ _ = normError "lookupPx'"
-- Internal lookup function which is generalised for arbitrary monads above.
lookup' :: Key -> StringMap a -> Maybe a
lookup' k t
= case lookupPx' k t of
Val v _ -> Just v
_ -> Nothing
-- ----------------------------------------
-- | /O(max(L,R))/ Find all values where the string is a prefix of the key.
prefixFind :: Key -> StringMap a -> [a]
prefixFind k = elems . lookupPx' k
-- | /O(max(L,R))/ Find all values where the string is a prefix of the key and include the keys
-- in the result.
prefixFindWithKey :: Key -> StringMap a -> [(Key, a)]
prefixFindWithKey k = fmap (first (k ++)) . toList . lookupPx' k
-- ----------------------------------------
insert' :: (a -> a -> a) -> a -> Key -> StringMap a -> StringMap a
insert' f v k0 = ins k0 . norm
where
ins' = insert' f v
ins k (Branch c' s' n')
= case k of
[] -> val v (branch c' s' n')
(c : k1)
| c < c' -> branch c (singleton k1 v) (branch c' s' n')
| c == c' -> branch c (ins' k1 s') n'
| otherwise -> branch c' s' (ins' k n')
ins k Empty = singleton k v
ins k (Val v' t')
= case k of
[] -> val (f v v') t'
_ -> val v' (ins' k t')
ins _ _ = normError "insert'"
-- ----------------------------------------
update' :: (a -> Maybe a) -> Key -> StringMap a -> StringMap a
update' f k0 = upd k0 . norm
where
upd' = update' f
upd k (Branch c' s' n')
= case k of
[] -> branch c' s' n'
(c : k1)
| c < c' -> branch c' s' n'
| c == c' -> branch c (upd' k1 s') n'
| otherwise -> branch c' s' (upd' k n')
upd _ Empty = empty
upd k (Val v' t')
= case k of
[] -> maybe t' (flip val t') $ f v'
_ -> val v' (upd' k t')
upd _ _ = normError "update'"
-- ----------------------------------------
-- | /O(n+m)/ Left-biased union of two maps. It prefers the first map when duplicate keys are
-- encountered, i.e. ('union' == 'unionWith' 'const').
union :: StringMap a -> StringMap a -> StringMap a
union = union' const
-- | /O(n+m)/ Union with a combining function.
unionWith :: (a -> a -> a) -> StringMap a -> StringMap a -> StringMap a
unionWith = union'
union' :: (a -> a -> a) -> StringMap a -> StringMap a -> StringMap a
union' f pt1 pt2 = uni (norm pt1) (norm pt2)
where
uni' t1' t2' = union' f (norm t1') (norm t2')
uni Empty Empty = empty
uni Empty (Val v2 t2) = val v2 t2
uni Empty (Branch c2 s2 n2)
= branch c2 s2 n2
uni (Val v1 t1) Empty = val v1 t1
uni (Val v1 t1) (Val v2 t2) = val (f v1 v2) (uni' t1 t2)
uni (Val v1 t1) t2@(Branch _ _ _) = val v1 (uni' t1 t2)
uni (Branch c1 s1 n1) Empty = branch c1 s1 n1
uni t1@(Branch _ _ _ ) (Val v2 t2) = val v2 (uni' t1 t2)
uni t1@(Branch c1 s1 n1) t2@(Branch c2 s2 n2)
| c1 < c2 = branch c1 s1 (uni' n1 t2)
| c1 > c2 = branch c2 s2 (uni' t1 n2)
| otherwise = branch c1 (uni' s1 s2) (uni' n1 n2)
uni _ _ = normError "union'"
-- ----------------------------------------
-- | /O(n+m)/ Union with a combining function, including the key.
unionWithKey :: (Key -> a -> a -> a) -> StringMap a -> StringMap a -> StringMap a
unionWithKey f = union'' f id
union'' :: (Key -> a -> a -> a) -> (Key -> Key) -> StringMap a -> StringMap a -> StringMap a
union'' f kf pt1 pt2 = uni (norm pt1) (norm pt2)
where
uni' t1' t2' = union'' f kf (norm t1') (norm t2')
uni Empty Empty = empty
uni Empty (Val v2 t2) = val v2 t2
uni Empty (Branch c2 s2 n2)
= branch c2 s2 n2
uni (Val v1 t1) Empty = val v1 t1
uni (Val v1 t1) (Val v2 t2) = val (f (kf []) v1 v2) (uni' t1 t2)
uni (Val v1 t1) t2@(Branch _ _ _) = val v1 (uni' t1 t2)
uni (Branch c1 s1 n1) Empty = branch c1 s1 n1
uni t1@(Branch _ _ _ ) (Val v2 t2) = val v2 (uni' t1 t2)
uni t1@(Branch c1 s1 n1) t2@(Branch c2 s2 n2)
| c1 < c2 = branch c1 s1 (uni' n1 t2)
| c1 > c2 = branch c2 s2 (uni' t1 n2)
| otherwise = branch c1 (union'' f (kf . (c1:)) s1 s2) (uni' n1 n2)
uni _ _ = normError "union''"
-- ----------------------------------------
--
-- | /(O(min(n,m))/ Difference between two tries (based on keys).
difference :: StringMap a -> StringMap b -> StringMap a
difference = differenceWith (const (const Nothing))
-- | /(O(min(n,m))/ Difference with a combining function. If the combining function always returns
-- 'Nothing', this is equal to proper set difference.
differenceWith :: (a -> b -> Maybe a) -> StringMap a -> StringMap b -> StringMap a
differenceWith f = differenceWithKey (const f)
-- | /O(min(n,m))/ Difference with a combining function, including the key. If two equal keys are
-- encountered, the combining function is applied to the key and both values. If it returns
-- 'Nothing', the element is discarded, if it returns 'Just' a value, the element is updated
-- with the new value.
differenceWithKey :: (Key -> a -> b -> Maybe a) -> StringMap a -> StringMap b -> StringMap a
differenceWithKey f = diff'' f id
diff'' :: (Key -> a -> b -> Maybe a) ->
(Key -> Key) ->
StringMap a -> StringMap b -> StringMap a
diff'' f kf pt1 pt2 = dif (norm pt1) (norm pt2)
where
dif' t1' t2' = diff'' f kf (norm t1') (norm t2')
dif Empty _ = empty
dif (Val v1 t1) Empty = val v1 t1
dif (Val v1 t1) (Val v2 t2) =
case f (kf []) v1 v2 of
Nothing -> dif' t1 t2
Just nv -> val nv (dif' t1 t2)
dif (Val v1 t1) t2@(Branch _ _ _) = val v1 (dif' t1 t2)
dif (Branch c1 s1 n1) Empty = branch c1 s1 n1
dif t1@(Branch _ _ _ ) (Val _ t2) = dif' t1 t2
dif t1@(Branch c1 s1 n1) t2@(Branch c2 s2 n2)
| c1 < c2 = branch c1 s1 (dif' n1 t2)
| c1 > c2 = dif' t1 n2
| otherwise = branch c1 (diff'' f (kf . (c1:)) s1 s2) (dif' n1 n2)
dif _ _ = normError "diff''"
-- ----------------------------------------
-- | cut off all branches from a tree @t2@ that are not part of set @t1@
--
-- the following laws must holds
--
-- @lookup' k' . cutPx' (singlePS k) $ t == lookup' k t@ for every @k'@ with @k@ prefix of @k'@
--
-- @lookup' k' . cutPx' (singlePS k) $ t == Nothing@ for every @k'@ with @k@ not being a prefix of @k'@
cutPx'' :: (StringMap a -> StringMap a) -> StringSet -> StringMap a -> StringMap a
cutPx'' cf s1' t2' = cut s1' (norm t2')
where
cut PSempty _t2 = empty
cut (PSelem _s1) t2 = cf t2
cut (PSnext _ _ _ ) Empty = empty
cut t1@(PSnext _ _ _ ) (Val _ t2) = cut t1 (norm t2)
cut t1@(PSnext c1 s1 n1) t2@(Branch c2 s2 n2)
| c1 < c2 = cut n1 t2
| c1 > c2 = cut t1 (norm n2)
| otherwise = branch c1 (cutPx'' cf s1 s2) (cutPx'' cf n1 n2)
cut _ _ = normError "cutPx''"
cutPx' :: StringSet -> StringMap a -> StringMap a
cutPx' = cutPx'' id
cutAllPx' :: StringSet -> StringMap a -> StringMap a
cutAllPx' = cutPx'' (cv . norm)
where
cv (Val v _) = val v empty
cv _ = empty
-- ----------------------------------------
-- | /O(n)/ Map a function over all values in the prefix tree.
map :: (a -> b) -> StringMap a -> StringMap b
map f = mapWithKey (const f)
mapWithKey :: (Key -> a -> b) -> StringMap a -> StringMap b
mapWithKey f = map' f id
map' :: (Key -> a -> b) -> (Key -> Key) -> StringMap a -> StringMap b
map' _ _ (Empty) = Empty
map' f k (Val v t) = Val (f (k []) v) (map' f k t)
map' f k (Branch c s n) = Branch c (map' f ((c :) . k) s) (map' f k n)
map' f k (Leaf v) = Leaf (f (k []) v)
map' f k (Last c s) = Last c (map' f ((c :) . k) s)
map' f k (LsSeq cs s) = LsSeq cs (map' f ((toKey cs ++) . k) s)
map' f k (BrSeq cs s n) = BrSeq cs (map' f ((toKey cs ++) . k) s) (map' f k n)
map' f k (LsSeL cs v) = LsSeL cs (f (k []) v)
map' f k (BrSeL cs v n) = BrSeL cs (f (k []) v) (map' f k n)
map' f k (LsVal c v) = LsVal c (f (k []) v)
map' f k (BrVal c v n) = BrVal c (f (k []) v) (map' f k n)
-- ----------------------------------------
{- not yet used
-- | Variant of map that works on normalized trees
mapN :: (a -> b) -> StringMap a -> StringMap b
mapN f = mapWithKeyN (const f)
mapWithKeyN :: (Key -> a -> b) -> StringMap a -> StringMap b
mapWithKeyN f = map'' f id
map'' :: (Key -> a -> b) -> (Key -> Key) -> StringMap a -> StringMap b
map'' f k = mapn . norm
where
mapn Empty = empty
mapn (Val v t) = val (f (k []) v) (map'' f k t)
mapn (Branch c s n) = branch c (map'' f ((c :) . k) s) (map'' f k n)
mapn _ = normError "map''"
-- -}
-- ----------------------------------------
-- | Monadic map
mapM :: Monad m => (a -> m b) -> StringMap a -> m (StringMap b)
mapM f = mapWithKeyM (const f)
-- | Monadic mapWithKey
mapWithKeyM :: Monad m => (Key -> a -> m b) -> StringMap a -> m (StringMap b)
mapWithKeyM f = mapM'' f id
mapM'' :: Monad m => (Key -> a -> m b) -> (Key -> Key) -> StringMap a -> m (StringMap b)
mapM'' f k = mapn . norm
where
mapn Empty = return $ empty
mapn (Val v t) = do
v' <- f (k []) v
t' <- mapM'' f k t
return $ val v' t'
mapn (Branch c s n) = do
s' <- mapM'' f ((c :) . k) s
n' <- mapM'' f k n
return $ branch c s' n'
mapn _ = normError "mapM''"
-- ----------------------------------------
--
-- A prefix tree visitor
data PrefixTreeVisitor a b = PTV
{ v_empty :: b
, v_val :: a -> b -> b
, v_branch :: Sym -> b -> b -> b
, v_leaf :: a -> b
, v_last :: Sym -> b -> b
, v_lsseq :: Key1 -> b -> b
, v_brseq :: Key1 -> b -> b -> b
, v_lssel :: Key1 -> a -> b
, v_brsel :: Key1 -> a -> b -> b
, v_lsval :: Sym -> a -> b
, v_brval :: Sym -> a -> b -> b
}
visit :: PrefixTreeVisitor a b -> StringMap a -> b
visit v (Empty) = v_empty v
visit v (Val v' t) = v_val v v' (visit v t)
visit v (Branch c s n) = v_branch v c (visit v s) (visit v n)
visit v (Leaf v') = v_leaf v v'
visit v (Last c s) = v_last v c (visit v s)
visit v (LsSeq cs s) = v_lsseq v cs (visit v s)
visit v (BrSeq cs s n) = v_brseq v cs (visit v s) (visit v n)
visit v (LsSeL cs v') = v_lssel v cs v'
visit v (BrSeL cs v' n) = v_brsel v cs v' (visit v n)
visit v (LsVal c v') = v_lsval v c v'
visit v (BrVal c v' n) = v_brval v c v' (visit v n)
-- ----------------------------------------
--
-- | space required by a prefix tree (logically)
--
-- Singletons are counted as 0, all other n-ary constructors
-- are counted as n+1 (1 for the constructor and 1 for every field)
-- cons nodes of char lists are counted 2, 1 for the cons, 1 for the char
-- for values only the ref to the value is counted, not the space for the value itself
-- key chars are assumed to be unboxed
space :: StringMap a -> Int
space = visit $
PTV
{ v_empty = 0
, v_val = const (3+)
, v_branch = const $ \ s n -> 4 + s + n
, v_leaf = const 2
, v_last = const (3+)
, v_lsseq = \ cs s -> 3 + 2 * length1 cs + s
, v_brseq = \ cs s n -> 4 + 2 * length1 cs + s + n
, v_lssel = \ cs _ -> 3 + 2 * length1 cs
, v_brsel = \ cs _ n -> 4 + 2 * length1 cs + n
, v_lsval = \ _ _ -> 3
, v_brval = \ _ _ n -> 4 + n
}
keyChars :: StringMap a -> Int
keyChars = visit $
PTV
{ v_empty = 0
, v_val = \ _ t -> t
, v_branch = \ _ s n -> 1 + s + n
, v_leaf = \ _ -> 0
, v_last = \ _ s -> 1 + s
, v_lsseq = \ cs s -> length1 cs + s
, v_brseq = \ cs s n -> length1 cs + s + n
, v_lssel = \ cs _ -> length1 cs
, v_brsel = \ cs _ n -> length1 cs + n
, v_lsval = \ _ _ -> 1
, v_brval = \ _ _ n -> 1 + n
}
-- ----------------------------------------
--
-- | statistics about the # of different nodes in an optimized prefix tree
stat :: StringMap a -> StringMap Int
stat = visit $
PTV
{ v_empty = singleton "empty" 1
, v_val = \ _ t -> singleton "val" 1 `add` t
, v_branch = \ _ s n -> singleton "branch" 1 `add` (s `add` n)
, v_leaf = \ _ -> singleton "leaf" 1
, v_last = \ _ s -> singleton "last" 1 `add` s
, v_lsseq = \ cs s -> singleton ("lsseq-" ++ show (length1 cs)) 1 `add` s
, v_brseq = \ cs s n -> singleton ("brseq-" ++ show (length1 cs)) 1 `add` (s `add` n)
, v_lssel = \ cs _ -> singleton ("lssel-" ++ show (length1 cs)) 1
, v_brsel = \ cs _ n -> singleton ("brseq-" ++ show (length1 cs)) 1 `add` n
, v_lsval = \ _ _ -> singleton "lsval" 1
, v_brval = \ _ _ n -> singleton "brval" 1 `add` n
}
where
add = unionWith (+)
-- ----------------------------------------
-- | /O(n)/ Fold over all key\/value pairs in the map.
foldWithKey :: (Key -> a -> b -> b) -> b -> StringMap a -> b
foldWithKey f e = fold' f e id
{-# INLINE foldWithKey #-}
-- | /O(n)/ Fold over all values in the map.
fold :: (a -> b -> b) -> b -> StringMap a -> b
fold f = foldWithKey $ const f
{-# INLINE fold #-}
{- not yet used
foldTopDown :: (Key -> a -> b -> b) -> b -> (Key -> Key) -> StringMap a -> b
foldTopDown f r k0 = fo k0 . norm
where
fo kf (Branch c' s' n') = let r' = foldTopDown f r ((c' :) . kf) s' in foldTopDown f r' kf n'
fo _ (Empty) = r
fo kf (Val v' t') = let r' = f (kf []) v' r in foldTopDown f r' kf t'
fo _ _ = normError "foldTopDown"
-- -}
fold' :: (Key -> a -> b -> b) -> b -> (Key -> Key) -> StringMap a -> b
fold' f r k0 = fo k0 . norm
where
fo kf (Branch c' s' n') = let r' = fold' f r kf n' in fold' f r' (kf . (c':)) s'
fo _ (Empty) = r
fo kf (Val v' t') = let r' = fold' f r kf t' in f (kf []) v' r'
fo _ _ = normError "fold'"
-- | /O(n)/ Convert into an ordinary map.
toMap :: StringMap a -> M.Map Key a
toMap = foldWithKey M.insert M.empty
-- | /O(n)/ Convert an ordinary map into a Prefix tree
fromMap :: M.Map Key a -> StringMap a
fromMap = M.foldrWithKey insert empty
-- | /O(n)/ Returns all elements as list of key value pairs,
toList :: StringMap a -> [(Key, a)]
toList = foldWithKey (\k v r -> (k, v) : r) []
-- | /O(n)/ Creates a trie from a list of key\/value pairs.
fromList :: [(Key, a)] -> StringMap a
fromList = L.foldl' (\p (k, v) -> insert k v p) empty
-- | /O(n)/ The number of elements.
size :: StringMap a -> Int
size = fold (const (+1)) 0
-- | /O(n)/ Returns all values.
elems :: StringMap a -> [a]
elems = fold (:) []
-- | /O(n)/ Returns all values.
keys :: StringMap a -> [Key]
keys = foldWithKey (\ k _v r -> k : r) []
-- ----------------------------------------
-- | returns all key-value pairs in breadth first order (short words first)
-- this enables prefix search with upper bounds on the size of the result set
-- e.g. @ search ... >>> toListBF >>> take 1000 @ will give the 1000 shortest words
-- found in the result set and will ignore all long words
--
-- toList is derived from the following code found in the net when searching haskell breadth first search
--
-- Haskell Standard Libraray Implementation
--
-- > br :: Tree a -> [a]
-- > br t = map rootLabel $
-- > concat $
-- > takeWhile (not . null) $
-- > iterate (concatMap subForest) [t]
toListBF :: StringMap v -> [(Key, v)]
toListBF = (\ t0 -> [(id, t0)])
>>>
iterate (concatMap (second norm >>> uncurry subForest))
>>>
takeWhile (not . L.null)
>>>
concat
>>>
concatMap (second norm >>> uncurry rootLabel)
rootLabel :: (Key -> Key) -> StringMap v -> [(Key, v)]
rootLabel kf (Val v _) = [(kf [], v)]
rootLabel _ _ = []
subForest :: (Key -> Key) -> StringMap v -> [(Key -> Key, StringMap v)]
subForest kf (Branch c s n) = (kf . (c:), s) : subForest kf (norm n)
subForest _ Empty = []
subForest kf (Val _ t) = subForest kf (norm t)
subForest _ _ = error "StringMap.Base.subForest: Pattern match failure"
-- ----------------------------------------
-- | /O(max(L,R))/ Find all values where the string is a prefix of the key and include the keys
-- in the result. The result list contains short words first
prefixFindWithKeyBF :: Key -> StringMap a -> [(Key, a)]
prefixFindWithKeyBF k = fmap (first (k ++)) . toListBF . lookupPx' k
-- ----------------------------------------
instance Functor StringMap where
fmap = map
instance Data.Foldable.Foldable StringMap where
foldr = fold
{- for debugging not yet enabled
instance Show a => Show (StringMap a) where
showsPrec d m = showParen (d > 10) $
showString "fromList " . shows (toList m)
-- -}
-- ----------------------------------------
instance Read a => Read (StringMap a) where
readsPrec p = readParen (p > 10) $
\ r -> do
("fromList",s) <- lex r
(xs,t) <- reads s
return (fromList xs,t)
-- ----------------------------------------
instance NFData a => NFData (StringMap a) where
rnf (Empty) = ()
rnf (Val v t) = rnf v `seq` rnf t
rnf (Branch _c s n) = rnf s `seq` rnf n
rnf (Leaf v) = rnf v
rnf (Last _c s) = rnf s
rnf (LsSeq _ks s) = rnf s
rnf (BrSeq _ks s n) = rnf s `seq` rnf n
rnf (LsSeL _ks v) = rnf v
rnf (BrSeL _ks v n) = rnf v `seq` rnf n
rnf (LsVal k v) = rnf k `seq` rnf v
rnf (BrVal k v n) = rnf k `seq` rnf v `seq` rnf n
-- ----------------------------------------
--
-- Provide native binary serialization (not via to-/fromList).
instance (Binary a) => Binary (StringMap a) where
put (Empty) = put (0::Word8)
put (Val v t) = put (1::Word8) >> put v >> put t
put (Branch c s n) = put (2::Word8) >> put c >> put s >> put n
put (Leaf v) = put (3::Word8) >> put v
put (Last c s) = put (4::Word8) >> put c >> put s
put (LsSeq k s) = put (5::Word8) >> put (toKey k) >> put s
put (BrSeq k s n) = put (6::Word8) >> put (toKey k) >> put s >> put n
put (LsSeL k v) = put (7::Word8) >> put (toKey k) >> put v
put (BrSeL k v n) = put (8::Word8) >> put (toKey k) >> put v >> put n
put (LsVal k v) = put (9::Word8) >> put k >> put v
put (BrVal k v n) = put (10::Word8) >> put k >> put v >> put n
get = do
!tag <- getWord8
case tag of
0 -> return Empty
1 -> do
!v <- get
!t <- get
return $! Val v t
2 -> do
!c <- get
!s <- get
!n <- get
return $! Branch c s n
3 -> do
!v <- get
return $! Leaf v
4 -> do
!c <- get
!s <- get
return $! Last c s
5 -> do
!k <- get
!s <- get
return $! LsSeq (fromKey k) s
6 -> do
!k <- get
!s <- get
!n <- get
return $! BrSeq (fromKey k) s n
7 -> do
!k <- get
!v <- get
return $! LsSeL (fromKey k) v
8 -> do
!k <- get
!v <- get
!n <- get
return $! BrSeL (fromKey k) v n
9 -> do
!k <- get
!v <- get
return $! LsVal k v
10 -> do
!k <- get
!v <- get
!n <- get
return $! BrVal k v n
_ -> fail "StringMap.get: error while decoding StringMap"
-- ----------------------------------------