/usr/lib/hugs/packages/fgl/Data/Graph/Inductive/Internal/FiniteMap.hs is in libhugs-fgl-bundled 98.200609.21-5.3.
This file is owned by root:root, with mode 0o644.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 | -- | Simple Finite Maps.
-- This implementation provides several useful methods that Data.FiniteMap
-- does not.
module Data.Graph.Inductive.Internal.FiniteMap(
-- * Type
FiniteMap(..),
-- * Operations
emptyFM,addToFM,delFromFM,
updFM,
accumFM,
splitFM,
isEmptyFM,sizeFM,lookupFM,elemFM,
rangeFM,
minFM,maxFM,predFM,succFM,
splitMinFM,
fmToList
) where
import Data.Maybe (isJust)
data Ord a => FiniteMap a b =
Empty | Node Int (FiniteMap a b) (a,b) (FiniteMap a b)
deriving (Eq)
----------------------------------------------------------------------
-- UTILITIES
----------------------------------------------------------------------
-- pretty printing
--
showsMap :: (Show a,Show b,Ord a) => FiniteMap a b -> ShowS
showsMap Empty = id
showsMap (Node _ l (i,x) r) = showsMap l . (' ':) .
shows i . ("->"++) . shows x . showsMap r
instance (Show a,Show b,Ord a) => Show (FiniteMap a b) where
showsPrec _ m = showsMap m
-- other
--
splitMax :: Ord a => FiniteMap a b -> (FiniteMap a b,(a,b))
splitMax (Node _ l x Empty) = (l,x)
splitMax (Node _ l x r) = (avlBalance l x m,y) where (m,y) = splitMax r
splitMax Empty = error "splitMax on empty FiniteMap"
merge :: Ord a => FiniteMap a b -> FiniteMap a b -> FiniteMap a b
merge l Empty = l
merge Empty r = r
merge l r = avlBalance l' x r where (l',x) = splitMax l
----------------------------------------------------------------------
-- MAIN FUNCTIONS
----------------------------------------------------------------------
emptyFM :: Ord a => FiniteMap a b
emptyFM = Empty
addToFM :: Ord a => FiniteMap a b -> a -> b -> FiniteMap a b
addToFM Empty i x = node Empty (i,x) Empty
addToFM (Node h l (j,y) r) i x
| i<j = avlBalance (addToFM l i x) (j,y) r
| i>j = avlBalance l (j,y) (addToFM r i x)
| otherwise = Node h l (j,x) r
-- | applies function to stored entry
updFM :: Ord a => FiniteMap a b -> a -> (b -> b) -> FiniteMap a b
updFM Empty _ _ = Empty
updFM (Node h l (j,x) r) i f
| i<j = let l' = updFM l i f in l' `seq` Node h l' (j,x) r
| i>j = let r' = updFM r i f in r' `seq` Node h l (j,x) r'
| otherwise = Node h l (j,f x) r
-- | defines or aggregates entries
accumFM :: Ord a => FiniteMap a b -> a -> (b -> b -> b) -> b -> FiniteMap a b
accumFM Empty i _ x = node Empty (i,x) Empty
accumFM (Node h l (j,y) r) i f x
| i<j = avlBalance (accumFM l i f x) (j,y) r
| i>j = avlBalance l (j,y) (accumFM r i f x)
| otherwise = Node h l (j,f x y) r
delFromFM :: Ord a => FiniteMap a b -> a -> FiniteMap a b
delFromFM Empty _ = Empty
delFromFM (Node _ l (j,x) r) i
| i<j = avlBalance (delFromFM l i) (j,x) r
| i>j = avlBalance l (j,x) (delFromFM r i)
| otherwise = merge l r
isEmptyFM :: FiniteMap a b -> Bool
isEmptyFM Empty = True
isEmptyFM _ = False
sizeFM :: Ord a => FiniteMap a b -> Int
sizeFM Empty = 0
sizeFM (Node _ l _ r) = sizeFM l + 1 + sizeFM r
lookupFM :: Ord a => FiniteMap a b -> a -> Maybe b
lookupFM Empty _ = Nothing
lookupFM (Node _ l (j,x) r) i | i<j = lookupFM l i
| i>j = lookupFM r i
| otherwise = Just x
-- | applies lookup to an interval
rangeFM :: Ord a => FiniteMap a b -> a -> a -> [b]
rangeFM m i j = rangeFMa m i j []
--
rangeFMa Empty _ _ a = a
rangeFMa (Node _ l (k,x) r) i j a
| k<i = rangeFMa r i j a
| k>j = rangeFMa l i j a
| otherwise = rangeFMa l i j (x:rangeFMa r i j a)
minFM :: Ord a => FiniteMap a b -> Maybe (a,b)
minFM Empty = Nothing
minFM (Node _ Empty x _) = Just x
minFM (Node _ l _ _) = minFM l
maxFM :: Ord a => FiniteMap a b -> Maybe (a,b)
maxFM Empty = Nothing
maxFM (Node _ _ x Empty) = Just x
maxFM (Node _ _ _ r) = maxFM r
predFM :: Ord a => FiniteMap a b -> a -> Maybe (a,b)
predFM m i = predFM' m i Nothing
--
predFM' Empty _ p = p
predFM' (Node _ l (j,x) r) i p | i<j = predFM' l i p
| i>j = predFM' r i (Just (j,x))
| isJust ml = ml
| otherwise = p
where ml = maxFM l
succFM :: Ord a => FiniteMap a b -> a -> Maybe (a,b)
succFM m i = succFM' m i Nothing
--
succFM' Empty _ p = p
succFM' (Node _ l (j,x) r) i p | i<j = succFM' l i (Just (j,x))
| i>j = succFM' r i p
| isJust mr = mr
| otherwise = p
where mr = minFM r
elemFM :: Ord a => FiniteMap a b -> a -> Bool
elemFM m i = case lookupFM m i of {Nothing -> False; _ -> True}
-- | combines delFrom and lookup
splitFM :: Ord a => FiniteMap a b -> a -> Maybe (FiniteMap a b,(a,b))
splitFM Empty _ = Nothing
splitFM (Node _ l (j,x) r) i =
if i<j then
case splitFM l i of
Just (l',y) -> Just (avlBalance l' (j,x) r,y)
Nothing -> Nothing else
if i>j then
case splitFM r i of
Just (r',y) -> Just (avlBalance l (j,x) r',y)
Nothing -> Nothing
else {- i==j -} Just (merge l r,(j,x))
-- | combines splitFM and minFM
splitMinFM :: Ord a => FiniteMap a b -> Maybe (FiniteMap a b,(a,b))
splitMinFM Empty = Nothing
splitMinFM (Node _ Empty x r) = Just (r,x)
splitMinFM (Node _ l x r) = Just (avlBalance l' x r,y)
where Just (l',y) = splitMinFM l
fmToList :: Ord a => FiniteMap a b -> [(a,b)]
fmToList m = scan m []
where scan Empty xs = xs
scan (Node _ l x r) xs = scan l (x:(scan r xs))
----------------------------------------------------------------------
-- AVL tree helper functions
----------------------------------------------------------------------
height :: Ord a => FiniteMap a b -> Int
height Empty = 0
height (Node h _ _ _) = h
node :: Ord a => FiniteMap a b -> (a,b) -> FiniteMap a b -> FiniteMap a b
node l val r = Node h l val r
where h=1+(height l `max` height r)
avlBalance :: Ord a => FiniteMap a b -> (a,b) -> FiniteMap a b -> FiniteMap a b
avlBalance l (i,x) r
| (hr + 1 < hl) && (bias l < 0) = rotr (node (rotl l) (i,x) r)
| (hr + 1 < hl) = rotr (node l (i,x) r)
| (hl + 1 < hr) && (0 < bias r) = rotl (node l (i,x) (rotr r))
| (hl + 1 < hr) = rotl (node l (i,x) r)
| otherwise = node l (i,x) r
where hl=height l; hr=height r
bias :: Ord a => FiniteMap a b -> Int
bias (Node _ l _ r) = height l - height r
bias Empty = 0
rotr :: Ord a => FiniteMap a b -> FiniteMap a b
rotr Empty = Empty
rotr (Node _ (Node _ l1 v1 r1) v2 r2) = node l1 v1 (node r1 v2 r2)
rotr (Node _ Empty _ _) = error "rotr on invalid FiniteMap"
rotl :: Ord a => FiniteMap a b -> FiniteMap a b
rotl Empty = Empty
rotl (Node _ l1 v1 (Node _ l2 v2 r2)) = node (node l1 v1 l2) v2 r2
rotl (Node _ _ _ Empty) = error "rotl on invalid FiniteMap"
|