1 {-# OPTIONS -cpp -fglasgow-exts #-}
2 -----------------------------------------------------------------------------
3 -- Module : Data.IntMap
4 -- Copyright : (c) Daan Leijen 2002
6 -- Maintainer : libraries@haskell.org
7 -- Stability : provisional
8 -- Portability : portable
10 -- An efficient implementation of maps from integer keys to values.
12 -- This module is intended to be imported @qualified@, to avoid name
13 -- clashes with "Prelude" functions. eg.
15 -- > import Data.IntMap as Map
17 -- The implementation is based on /big-endian patricia trees/. This data
18 -- structure performs especially well on binary operations like 'union'
19 -- and 'intersection'. However, my benchmarks show that it is also
20 -- (much) faster on insertions and deletions when compared to a generic
21 -- size-balanced map implementation (see "Data.Map" and "Data.FiniteMap").
23 -- * Chris Okasaki and Andy Gill, \"/Fast Mergeable Integer Maps/\",
24 -- Workshop on ML, September 1998, pages 77-86,
25 -- <http://www.cse.ogi.edu/~andy/pub/finite.htm>
27 -- * D.R. Morrison, \"/PATRICIA -- Practical Algorithm To Retrieve
28 -- Information Coded In Alphanumeric/\", Journal of the ACM, 15(4),
29 -- October 1968, pages 514-534.
31 -- Many operations have a worst-case complexity of /O(min(n,W))/.
32 -- This means that the operation can become linear in the number of
33 -- elements with a maximum of /W/ -- the number of bits in an 'Int'
35 -----------------------------------------------------------------------------
39 IntMap, Key -- instance Eq,Show
57 , insertWith, insertWithKey, insertLookupWithKey
114 , fromDistinctAscList
126 , isSubmapOf, isSubmapOfBy
127 , isProperSubmapOf, isProperSubmapOfBy
135 import Prelude hiding (lookup,map,filter,foldr,foldl,null)
138 import qualified Data.IntSet as IntSet
139 import Data.Monoid (Monoid(..))
144 import qualified Prelude
145 import Debug.QuickCheck
146 import List (nub,sort)
147 import qualified List
150 #if __GLASGOW_HASKELL__
152 import Data.Generics.Basics
153 import Data.Generics.Instances
156 #if __GLASGOW_HASKELL__ >= 503
158 import GHC.Exts ( Word(..), Int(..), shiftRL# )
159 #elif __GLASGOW_HASKELL__
161 import GlaExts ( Word(..), Int(..), shiftRL# )
166 infixl 9 \\{-This comment teaches CPP correct behaviour -}
168 -- A "Nat" is a natural machine word (an unsigned Int)
171 natFromInt :: Key -> Nat
172 natFromInt i = fromIntegral i
174 intFromNat :: Nat -> Key
175 intFromNat w = fromIntegral w
177 shiftRL :: Nat -> Key -> Nat
178 #if __GLASGOW_HASKELL__
179 {--------------------------------------------------------------------
180 GHC: use unboxing to get @shiftRL@ inlined.
181 --------------------------------------------------------------------}
182 shiftRL (W# x) (I# i)
185 shiftRL x i = shiftR x i
188 {--------------------------------------------------------------------
190 --------------------------------------------------------------------}
192 -- | /O(min(n,W))/. Find the value at a key.
193 -- Calls 'error' when the element can not be found.
195 (!) :: IntMap a -> Key -> a
198 -- | /O(n+m)/. See 'difference'.
199 (\\) :: IntMap a -> IntMap b -> IntMap a
200 m1 \\ m2 = difference m1 m2
202 {--------------------------------------------------------------------
204 --------------------------------------------------------------------}
205 -- | A map of integers to values @a@.
207 | Tip {-# UNPACK #-} !Key a
208 | Bin {-# UNPACK #-} !Prefix {-# UNPACK #-} !Mask !(IntMap a) !(IntMap a)
214 instance Ord a => Monoid (IntMap a) where
219 #if __GLASGOW_HASKELL__
221 {--------------------------------------------------------------------
223 --------------------------------------------------------------------}
225 -- This instance preserves data abstraction at the cost of inefficiency.
226 -- We omit reflection services for the sake of data abstraction.
228 instance Data a => Data (IntMap a) where
229 gfoldl f z im = z fromList `f` (toList im)
230 toConstr _ = error "toConstr"
231 gunfold _ _ = error "gunfold"
232 dataTypeOf _ = mkNorepType "Data.IntMap.IntMap"
236 {--------------------------------------------------------------------
238 --------------------------------------------------------------------}
239 -- | /O(1)/. Is the map empty?
240 null :: IntMap a -> Bool
244 -- | /O(n)/. Number of elements in the map.
245 size :: IntMap a -> Int
248 Bin p m l r -> size l + size r
252 -- | /O(min(n,W))/. Is the key a member of the map?
253 member :: Key -> IntMap a -> Bool
259 -- | /O(min(n,W))/. Lookup the value at a key in the map.
260 lookup :: Key -> IntMap a -> Maybe a
262 = let nk = natFromInt k in seq nk (lookupN nk t)
264 lookupN :: Nat -> IntMap a -> Maybe a
268 | zeroN k (natFromInt m) -> lookupN k l
269 | otherwise -> lookupN k r
271 | (k == natFromInt kx) -> Just x
272 | otherwise -> Nothing
275 find' :: Key -> IntMap a -> a
278 Nothing -> error ("IntMap.find: key " ++ show k ++ " is not an element of the map")
282 -- | /O(min(n,W))/. The expression @('findWithDefault' def k map)@
283 -- returns the value at key @k@ or returns @def@ when the key is not an
284 -- element of the map.
285 findWithDefault :: a -> Key -> IntMap a -> a
286 findWithDefault def k m
291 {--------------------------------------------------------------------
293 --------------------------------------------------------------------}
294 -- | /O(1)/. The empty map.
299 -- | /O(1)/. A map of one element.
300 singleton :: Key -> a -> IntMap a
304 {--------------------------------------------------------------------
306 --------------------------------------------------------------------}
307 -- | /O(min(n,W))/. Insert a new key\/value pair in the map.
308 -- If the key is already present in the map, the associated value is
309 -- replaced with the supplied value, i.e. 'insert' is equivalent to
310 -- @'insertWith' 'const'@.
311 insert :: Key -> a -> IntMap a -> IntMap a
315 | nomatch k p m -> join k (Tip k x) p t
316 | zero k m -> Bin p m (insert k x l) r
317 | otherwise -> Bin p m l (insert k x r)
320 | otherwise -> join k (Tip k x) ky t
323 -- right-biased insertion, used by 'union'
324 -- | /O(min(n,W))/. Insert with a combining function.
325 -- @'insertWith' f key value mp@
326 -- will insert the pair (key, value) into @mp@ if key does
327 -- not exist in the map. If the key does exist, the function will
328 -- insert @f new_value old_value@.
329 insertWith :: (a -> a -> a) -> Key -> a -> IntMap a -> IntMap a
331 = insertWithKey (\k x y -> f x y) k x t
333 -- | /O(min(n,W))/. Insert with a combining function.
334 -- @'insertWithKey' f key value mp@
335 -- will insert the pair (key, value) into @mp@ if key does
336 -- not exist in the map. If the key does exist, the function will
337 -- insert @f key new_value old_value@.
338 insertWithKey :: (Key -> a -> a -> a) -> Key -> a -> IntMap a -> IntMap a
339 insertWithKey f k x t
342 | nomatch k p m -> join k (Tip k x) p t
343 | zero k m -> Bin p m (insertWithKey f k x l) r
344 | otherwise -> Bin p m l (insertWithKey f k x r)
346 | k==ky -> Tip k (f k x y)
347 | otherwise -> join k (Tip k x) ky t
351 -- | /O(min(n,W))/. The expression (@'insertLookupWithKey' f k x map@)
352 -- is a pair where the first element is equal to (@'lookup' k map@)
353 -- and the second element equal to (@'insertWithKey' f k x map@).
354 insertLookupWithKey :: (Key -> a -> a -> a) -> Key -> a -> IntMap a -> (Maybe a, IntMap a)
355 insertLookupWithKey f k x t
358 | nomatch k p m -> (Nothing,join k (Tip k x) p t)
359 | zero k m -> let (found,l') = insertLookupWithKey f k x l in (found,Bin p m l' r)
360 | otherwise -> let (found,r') = insertLookupWithKey f k x r in (found,Bin p m l r')
362 | k==ky -> (Just y,Tip k (f k x y))
363 | otherwise -> (Nothing,join k (Tip k x) ky t)
364 Nil -> (Nothing,Tip k x)
367 {--------------------------------------------------------------------
369 [delete] is the inlined version of [deleteWith (\k x -> Nothing)]
370 --------------------------------------------------------------------}
371 -- | /O(min(n,W))/. Delete a key and its value from the map. When the key is not
372 -- a member of the map, the original map is returned.
373 delete :: Key -> IntMap a -> IntMap a
378 | zero k m -> bin p m (delete k l) r
379 | otherwise -> bin p m l (delete k r)
385 -- | /O(min(n,W))/. Adjust a value at a specific key. When the key is not
386 -- a member of the map, the original map is returned.
387 adjust :: (a -> a) -> Key -> IntMap a -> IntMap a
389 = adjustWithKey (\k x -> f x) k m
391 -- | /O(min(n,W))/. Adjust a value at a specific key. When the key is not
392 -- a member of the map, the original map is returned.
393 adjustWithKey :: (Key -> a -> a) -> Key -> IntMap a -> IntMap a
395 = updateWithKey (\k x -> Just (f k x)) k m
397 -- | /O(min(n,W))/. The expression (@'update' f k map@) updates the value @x@
398 -- at @k@ (if it is in the map). If (@f x@) is 'Nothing', the element is
399 -- deleted. If it is (@'Just' y@), the key @k@ is bound to the new value @y@.
400 update :: (a -> Maybe a) -> Key -> IntMap a -> IntMap a
402 = updateWithKey (\k x -> f x) k m
404 -- | /O(min(n,W))/. The expression (@'update' f k map@) updates the value @x@
405 -- at @k@ (if it is in the map). If (@f k x@) is 'Nothing', the element is
406 -- deleted. If it is (@'Just' y@), the key @k@ is bound to the new value @y@.
407 updateWithKey :: (Key -> a -> Maybe a) -> Key -> IntMap a -> IntMap a
412 | zero k m -> bin p m (updateWithKey f k l) r
413 | otherwise -> bin p m l (updateWithKey f k r)
415 | k==ky -> case (f k y) of
421 -- | /O(min(n,W))/. Lookup and update.
422 updateLookupWithKey :: (Key -> a -> Maybe a) -> Key -> IntMap a -> (Maybe a,IntMap a)
423 updateLookupWithKey f k t
426 | nomatch k p m -> (Nothing,t)
427 | zero k m -> let (found,l') = updateLookupWithKey f k l in (found,bin p m l' r)
428 | otherwise -> let (found,r') = updateLookupWithKey f k r in (found,bin p m l r')
430 | k==ky -> case (f k y) of
431 Just y' -> (Just y,Tip ky y')
432 Nothing -> (Just y,Nil)
433 | otherwise -> (Nothing,t)
437 {--------------------------------------------------------------------
439 --------------------------------------------------------------------}
440 -- | The union of a list of maps.
441 unions :: [IntMap a] -> IntMap a
443 = foldlStrict union empty xs
445 -- | The union of a list of maps, with a combining operation
446 unionsWith :: (a->a->a) -> [IntMap a] -> IntMap a
448 = foldlStrict (unionWith f) empty ts
450 -- | /O(n+m)/. The (left-biased) union of two maps.
451 -- It prefers the first map when duplicate keys are encountered,
452 -- i.e. (@'union' == 'unionWith' 'const'@).
453 union :: IntMap a -> IntMap a -> IntMap a
454 union t1@(Bin p1 m1 l1 r1) t2@(Bin p2 m2 l2 r2)
455 | shorter m1 m2 = union1
456 | shorter m2 m1 = union2
457 | p1 == p2 = Bin p1 m1 (union l1 l2) (union r1 r2)
458 | otherwise = join p1 t1 p2 t2
460 union1 | nomatch p2 p1 m1 = join p1 t1 p2 t2
461 | zero p2 m1 = Bin p1 m1 (union l1 t2) r1
462 | otherwise = Bin p1 m1 l1 (union r1 t2)
464 union2 | nomatch p1 p2 m2 = join p1 t1 p2 t2
465 | zero p1 m2 = Bin p2 m2 (union t1 l2) r2
466 | otherwise = Bin p2 m2 l2 (union t1 r2)
468 union (Tip k x) t = insert k x t
469 union t (Tip k x) = insertWith (\x y -> y) k x t -- right bias
473 -- | /O(n+m)/. The union with a combining function.
474 unionWith :: (a -> a -> a) -> IntMap a -> IntMap a -> IntMap a
476 = unionWithKey (\k x y -> f x y) m1 m2
478 -- | /O(n+m)/. The union with a combining function.
479 unionWithKey :: (Key -> a -> a -> a) -> IntMap a -> IntMap a -> IntMap a
480 unionWithKey f t1@(Bin p1 m1 l1 r1) t2@(Bin p2 m2 l2 r2)
481 | shorter m1 m2 = union1
482 | shorter m2 m1 = union2
483 | p1 == p2 = Bin p1 m1 (unionWithKey f l1 l2) (unionWithKey f r1 r2)
484 | otherwise = join p1 t1 p2 t2
486 union1 | nomatch p2 p1 m1 = join p1 t1 p2 t2
487 | zero p2 m1 = Bin p1 m1 (unionWithKey f l1 t2) r1
488 | otherwise = Bin p1 m1 l1 (unionWithKey f r1 t2)
490 union2 | nomatch p1 p2 m2 = join p1 t1 p2 t2
491 | zero p1 m2 = Bin p2 m2 (unionWithKey f t1 l2) r2
492 | otherwise = Bin p2 m2 l2 (unionWithKey f t1 r2)
494 unionWithKey f (Tip k x) t = insertWithKey f k x t
495 unionWithKey f t (Tip k x) = insertWithKey (\k x y -> f k y x) k x t -- right bias
496 unionWithKey f Nil t = t
497 unionWithKey f t Nil = t
499 {--------------------------------------------------------------------
501 --------------------------------------------------------------------}
502 -- | /O(n+m)/. Difference between two maps (based on keys).
503 difference :: IntMap a -> IntMap b -> IntMap a
504 difference t1@(Bin p1 m1 l1 r1) t2@(Bin p2 m2 l2 r2)
505 | shorter m1 m2 = difference1
506 | shorter m2 m1 = difference2
507 | p1 == p2 = bin p1 m1 (difference l1 l2) (difference r1 r2)
510 difference1 | nomatch p2 p1 m1 = t1
511 | zero p2 m1 = bin p1 m1 (difference l1 t2) r1
512 | otherwise = bin p1 m1 l1 (difference r1 t2)
514 difference2 | nomatch p1 p2 m2 = t1
515 | zero p1 m2 = difference t1 l2
516 | otherwise = difference t1 r2
518 difference t1@(Tip k x) t2
522 difference Nil t = Nil
523 difference t (Tip k x) = delete k t
526 -- | /O(n+m)/. Difference with a combining function.
527 differenceWith :: (a -> b -> Maybe a) -> IntMap a -> IntMap b -> IntMap a
528 differenceWith f m1 m2
529 = differenceWithKey (\k x y -> f x y) m1 m2
531 -- | /O(n+m)/. Difference with a combining function. When two equal keys are
532 -- encountered, the combining function is applied to the key and both values.
533 -- If it returns 'Nothing', the element is discarded (proper set difference).
534 -- If it returns (@'Just' y@), the element is updated with a new value @y@.
535 differenceWithKey :: (Key -> a -> b -> Maybe a) -> IntMap a -> IntMap b -> IntMap a
536 differenceWithKey f t1@(Bin p1 m1 l1 r1) t2@(Bin p2 m2 l2 r2)
537 | shorter m1 m2 = difference1
538 | shorter m2 m1 = difference2
539 | p1 == p2 = bin p1 m1 (differenceWithKey f l1 l2) (differenceWithKey f r1 r2)
542 difference1 | nomatch p2 p1 m1 = t1
543 | zero p2 m1 = bin p1 m1 (differenceWithKey f l1 t2) r1
544 | otherwise = bin p1 m1 l1 (differenceWithKey f r1 t2)
546 difference2 | nomatch p1 p2 m2 = t1
547 | zero p1 m2 = differenceWithKey f t1 l2
548 | otherwise = differenceWithKey f t1 r2
550 differenceWithKey f t1@(Tip k x) t2
551 = case lookup k t2 of
552 Just y -> case f k x y of
557 differenceWithKey f Nil t = Nil
558 differenceWithKey f t (Tip k y) = updateWithKey (\k x -> f k x y) k t
559 differenceWithKey f t Nil = t
562 {--------------------------------------------------------------------
564 --------------------------------------------------------------------}
565 -- | /O(n+m)/. The (left-biased) intersection of two maps (based on keys).
566 intersection :: IntMap a -> IntMap b -> IntMap a
567 intersection t1@(Bin p1 m1 l1 r1) t2@(Bin p2 m2 l2 r2)
568 | shorter m1 m2 = intersection1
569 | shorter m2 m1 = intersection2
570 | p1 == p2 = bin p1 m1 (intersection l1 l2) (intersection r1 r2)
573 intersection1 | nomatch p2 p1 m1 = Nil
574 | zero p2 m1 = intersection l1 t2
575 | otherwise = intersection r1 t2
577 intersection2 | nomatch p1 p2 m2 = Nil
578 | zero p1 m2 = intersection t1 l2
579 | otherwise = intersection t1 r2
581 intersection t1@(Tip k x) t2
584 intersection t (Tip k x)
588 intersection Nil t = Nil
589 intersection t Nil = Nil
591 -- | /O(n+m)/. The intersection with a combining function.
592 intersectionWith :: (a -> b -> a) -> IntMap a -> IntMap b -> IntMap a
593 intersectionWith f m1 m2
594 = intersectionWithKey (\k x y -> f x y) m1 m2
596 -- | /O(n+m)/. The intersection with a combining function.
597 intersectionWithKey :: (Key -> a -> b -> a) -> IntMap a -> IntMap b -> IntMap a
598 intersectionWithKey f t1@(Bin p1 m1 l1 r1) t2@(Bin p2 m2 l2 r2)
599 | shorter m1 m2 = intersection1
600 | shorter m2 m1 = intersection2
601 | p1 == p2 = bin p1 m1 (intersectionWithKey f l1 l2) (intersectionWithKey f r1 r2)
604 intersection1 | nomatch p2 p1 m1 = Nil
605 | zero p2 m1 = intersectionWithKey f l1 t2
606 | otherwise = intersectionWithKey f r1 t2
608 intersection2 | nomatch p1 p2 m2 = Nil
609 | zero p1 m2 = intersectionWithKey f t1 l2
610 | otherwise = intersectionWithKey f t1 r2
612 intersectionWithKey f t1@(Tip k x) t2
613 = case lookup k t2 of
614 Just y -> Tip k (f k x y)
616 intersectionWithKey f t1 (Tip k y)
617 = case lookup k t1 of
618 Just x -> Tip k (f k x y)
620 intersectionWithKey f Nil t = Nil
621 intersectionWithKey f t Nil = Nil
624 {--------------------------------------------------------------------
626 --------------------------------------------------------------------}
627 -- | /O(n+m)/. Is this a proper submap? (ie. a submap but not equal).
628 -- Defined as (@'isProperSubmapOf' = 'isProperSubmapOfBy' (==)@).
629 isProperSubmapOf :: Eq a => IntMap a -> IntMap a -> Bool
630 isProperSubmapOf m1 m2
631 = isProperSubmapOfBy (==) m1 m2
633 {- | /O(n+m)/. Is this a proper submap? (ie. a submap but not equal).
634 The expression (@'isProperSubmapOfBy' f m1 m2@) returns 'True' when
635 @m1@ and @m2@ are not equal,
636 all keys in @m1@ are in @m2@, and when @f@ returns 'True' when
637 applied to their respective values. For example, the following
638 expressions are all 'True':
640 > isProperSubmapOfBy (==) (fromList [(1,1)]) (fromList [(1,1),(2,2)])
641 > isProperSubmapOfBy (<=) (fromList [(1,1)]) (fromList [(1,1),(2,2)])
643 But the following are all 'False':
645 > isProperSubmapOfBy (==) (fromList [(1,1),(2,2)]) (fromList [(1,1),(2,2)])
646 > isProperSubmapOfBy (==) (fromList [(1,1),(2,2)]) (fromList [(1,1)])
647 > isProperSubmapOfBy (<) (fromList [(1,1)]) (fromList [(1,1),(2,2)])
649 isProperSubmapOfBy :: (a -> b -> Bool) -> IntMap a -> IntMap b -> Bool
650 isProperSubmapOfBy pred t1 t2
651 = case submapCmp pred t1 t2 of
655 submapCmp pred t1@(Bin p1 m1 l1 r1) t2@(Bin p2 m2 l2 r2)
657 | shorter m2 m1 = submapCmpLt
658 | p1 == p2 = submapCmpEq
659 | otherwise = GT -- disjoint
661 submapCmpLt | nomatch p1 p2 m2 = GT
662 | zero p1 m2 = submapCmp pred t1 l2
663 | otherwise = submapCmp pred t1 r2
664 submapCmpEq = case (submapCmp pred l1 l2, submapCmp pred r1 r2) of
670 submapCmp pred (Bin p m l r) t = GT
671 submapCmp pred (Tip kx x) (Tip ky y)
672 | (kx == ky) && pred x y = EQ
673 | otherwise = GT -- disjoint
674 submapCmp pred (Tip k x) t
676 Just y | pred x y -> LT
677 other -> GT -- disjoint
678 submapCmp pred Nil Nil = EQ
679 submapCmp pred Nil t = LT
681 -- | /O(n+m)/. Is this a submap?
682 -- Defined as (@'isSubmapOf' = 'isSubmapOfBy' (==)@).
683 isSubmapOf :: Eq a => IntMap a -> IntMap a -> Bool
685 = isSubmapOfBy (==) m1 m2
688 The expression (@'isSubmapOfBy' f m1 m2@) returns 'True' if
689 all keys in @m1@ are in @m2@, and when @f@ returns 'True' when
690 applied to their respective values. For example, the following
691 expressions are all 'True':
693 > isSubmapOfBy (==) (fromList [(1,1)]) (fromList [(1,1),(2,2)])
694 > isSubmapOfBy (<=) (fromList [(1,1)]) (fromList [(1,1),(2,2)])
695 > isSubmapOfBy (==) (fromList [(1,1),(2,2)]) (fromList [(1,1),(2,2)])
697 But the following are all 'False':
699 > isSubmapOfBy (==) (fromList [(1,2)]) (fromList [(1,1),(2,2)])
700 > isSubmapOfBy (<) (fromList [(1,1)]) (fromList [(1,1),(2,2)])
701 > isSubmapOfBy (==) (fromList [(1,1),(2,2)]) (fromList [(1,1)])
704 isSubmapOfBy :: (a -> b -> Bool) -> IntMap a -> IntMap b -> Bool
705 isSubmapOfBy pred t1@(Bin p1 m1 l1 r1) t2@(Bin p2 m2 l2 r2)
706 | shorter m1 m2 = False
707 | shorter m2 m1 = match p1 p2 m2 && (if zero p1 m2 then isSubmapOfBy pred t1 l2
708 else isSubmapOfBy pred t1 r2)
709 | otherwise = (p1==p2) && isSubmapOfBy pred l1 l2 && isSubmapOfBy pred r1 r2
710 isSubmapOfBy pred (Bin p m l r) t = False
711 isSubmapOfBy pred (Tip k x) t = case lookup k t of
714 isSubmapOfBy pred Nil t = True
716 {--------------------------------------------------------------------
718 --------------------------------------------------------------------}
719 -- | /O(n)/. Map a function over all values in the map.
720 map :: (a -> b) -> IntMap a -> IntMap b
722 = mapWithKey (\k x -> f x) m
724 -- | /O(n)/. Map a function over all values in the map.
725 mapWithKey :: (Key -> a -> b) -> IntMap a -> IntMap b
728 Bin p m l r -> Bin p m (mapWithKey f l) (mapWithKey f r)
729 Tip k x -> Tip k (f k x)
732 -- | /O(n)/. The function @'mapAccum'@ threads an accumulating
733 -- argument through the map in ascending order of keys.
734 mapAccum :: (a -> b -> (a,c)) -> a -> IntMap b -> (a,IntMap c)
736 = mapAccumWithKey (\a k x -> f a x) a m
738 -- | /O(n)/. The function @'mapAccumWithKey'@ threads an accumulating
739 -- argument through the map in ascending order of keys.
740 mapAccumWithKey :: (a -> Key -> b -> (a,c)) -> a -> IntMap b -> (a,IntMap c)
741 mapAccumWithKey f a t
744 -- | /O(n)/. The function @'mapAccumL'@ threads an accumulating
745 -- argument through the map in ascending order of keys.
746 mapAccumL :: (a -> Key -> b -> (a,c)) -> a -> IntMap b -> (a,IntMap c)
749 Bin p m l r -> let (a1,l') = mapAccumL f a l
750 (a2,r') = mapAccumL f a1 r
751 in (a2,Bin p m l' r')
752 Tip k x -> let (a',x') = f a k x in (a',Tip k x')
756 -- | /O(n)/. The function @'mapAccumR'@ threads an accumulating
757 -- argument throught the map in descending order of keys.
758 mapAccumR :: (a -> Key -> b -> (a,c)) -> a -> IntMap b -> (a,IntMap c)
761 Bin p m l r -> let (a1,r') = mapAccumR f a r
762 (a2,l') = mapAccumR f a1 l
763 in (a2,Bin p m l' r')
764 Tip k x -> let (a',x') = f a k x in (a',Tip k x')
767 {--------------------------------------------------------------------
769 --------------------------------------------------------------------}
770 -- | /O(n)/. Filter all values that satisfy some predicate.
771 filter :: (a -> Bool) -> IntMap a -> IntMap a
773 = filterWithKey (\k x -> p x) m
775 -- | /O(n)/. Filter all keys\/values that satisfy some predicate.
776 filterWithKey :: (Key -> a -> Bool) -> IntMap a -> IntMap a
780 -> bin p m (filterWithKey pred l) (filterWithKey pred r)
786 -- | /O(n)/. partition the map according to some predicate. The first
787 -- map contains all elements that satisfy the predicate, the second all
788 -- elements that fail the predicate. See also 'split'.
789 partition :: (a -> Bool) -> IntMap a -> (IntMap a,IntMap a)
791 = partitionWithKey (\k x -> p x) m
793 -- | /O(n)/. partition the map according to some predicate. The first
794 -- map contains all elements that satisfy the predicate, the second all
795 -- elements that fail the predicate. See also 'split'.
796 partitionWithKey :: (Key -> a -> Bool) -> IntMap a -> (IntMap a,IntMap a)
797 partitionWithKey pred t
800 -> let (l1,l2) = partitionWithKey pred l
801 (r1,r2) = partitionWithKey pred r
802 in (bin p m l1 r1, bin p m l2 r2)
804 | pred k x -> (t,Nil)
805 | otherwise -> (Nil,t)
809 -- | /O(log n)/. The expression (@'split' k map@) is a pair @(map1,map2)@
810 -- where all keys in @map1@ are lower than @k@ and all keys in
811 -- @map2@ larger than @k@. Any key equal to @k@ is found in neither @map1@ nor @map2@.
812 split :: Key -> IntMap a -> (IntMap a,IntMap a)
816 | m < 0 -> (if k >= 0 -- handle negative numbers.
817 then let (lt,gt) = split' k l in (union r lt, gt)
818 else let (lt,gt) = split' k r in (lt, union gt l))
819 | otherwise -> split' k t
823 | otherwise -> (Nil,Nil)
826 split' :: Key -> IntMap a -> (IntMap a,IntMap a)
830 | nomatch k p m -> if k>p then (t,Nil) else (Nil,t)
831 | zero k m -> let (lt,gt) = split k l in (lt,union gt r)
832 | otherwise -> let (lt,gt) = split k r in (union l lt,gt)
836 | otherwise -> (Nil,Nil)
839 -- | /O(log n)/. Performs a 'split' but also returns whether the pivot
840 -- key was found in the original map.
841 splitLookup :: Key -> IntMap a -> (IntMap a,Maybe a,IntMap a)
845 | m < 0 -> (if k >= 0 -- handle negative numbers.
846 then let (lt,found,gt) = splitLookup' k l in (union r lt,found, gt)
847 else let (lt,found,gt) = splitLookup' k r in (lt,found, union gt l))
848 | otherwise -> splitLookup' k t
850 | k>ky -> (t,Nothing,Nil)
851 | k<ky -> (Nil,Nothing,t)
852 | otherwise -> (Nil,Just y,Nil)
853 Nil -> (Nil,Nothing,Nil)
855 splitLookup' :: Key -> IntMap a -> (IntMap a,Maybe a,IntMap a)
859 | nomatch k p m -> if k>p then (t,Nothing,Nil) else (Nil,Nothing,t)
860 | zero k m -> let (lt,found,gt) = splitLookup k l in (lt,found,union gt r)
861 | otherwise -> let (lt,found,gt) = splitLookup k r in (union l lt,found,gt)
863 | k>ky -> (t,Nothing,Nil)
864 | k<ky -> (Nil,Nothing,t)
865 | otherwise -> (Nil,Just y,Nil)
866 Nil -> (Nil,Nothing,Nil)
868 {--------------------------------------------------------------------
870 --------------------------------------------------------------------}
871 -- | /O(n)/. Fold the values in the map, such that
872 -- @'fold' f z == 'Prelude.foldr' f z . 'elems'@.
875 -- > elems map = fold (:) [] map
877 fold :: (a -> b -> b) -> b -> IntMap a -> b
879 = foldWithKey (\k x y -> f x y) z t
881 -- | /O(n)/. Fold the keys and values in the map, such that
882 -- @'foldWithKey' f z == 'Prelude.foldr' ('uncurry' f) z . 'toAscList'@.
885 -- > keys map = foldWithKey (\k x ks -> k:ks) [] map
887 foldWithKey :: (Key -> a -> b -> b) -> b -> IntMap a -> b
891 foldr :: (Key -> a -> b -> b) -> b -> IntMap a -> b
894 Bin 0 m l r | m < 0 -> foldr' f (foldr' f z l) r -- put negative numbers before.
895 Bin _ _ _ _ -> foldr' f z t
899 foldr' :: (Key -> a -> b -> b) -> b -> IntMap a -> b
902 Bin p m l r -> foldr' f (foldr' f z r) l
908 {--------------------------------------------------------------------
910 --------------------------------------------------------------------}
912 -- Return all elements of the map in the ascending order of their keys.
913 elems :: IntMap a -> [a]
915 = foldWithKey (\k x xs -> x:xs) [] m
917 -- | /O(n)/. Return all keys of the map in ascending order.
918 keys :: IntMap a -> [Key]
920 = foldWithKey (\k x ks -> k:ks) [] m
922 -- | /O(n*min(n,W))/. The set of all keys of the map.
923 keysSet :: IntMap a -> IntSet.IntSet
924 keysSet m = IntSet.fromDistinctAscList (keys m)
927 -- | /O(n)/. Return all key\/value pairs in the map in ascending key order.
928 assocs :: IntMap a -> [(Key,a)]
933 {--------------------------------------------------------------------
935 --------------------------------------------------------------------}
936 -- | /O(n)/. Convert the map to a list of key\/value pairs.
937 toList :: IntMap a -> [(Key,a)]
939 = foldWithKey (\k x xs -> (k,x):xs) [] t
941 -- | /O(n)/. Convert the map to a list of key\/value pairs where the
942 -- keys are in ascending order.
943 toAscList :: IntMap a -> [(Key,a)]
945 = -- NOTE: the following algorithm only works for big-endian trees
946 let (pos,neg) = span (\(k,x) -> k >=0) (foldr (\k x xs -> (k,x):xs) [] t) in neg ++ pos
948 -- | /O(n*min(n,W))/. Create a map from a list of key\/value pairs.
949 fromList :: [(Key,a)] -> IntMap a
951 = foldlStrict ins empty xs
953 ins t (k,x) = insert k x t
955 -- | /O(n*min(n,W))/. Create a map from a list of key\/value pairs with a combining function. See also 'fromAscListWith'.
956 fromListWith :: (a -> a -> a) -> [(Key,a)] -> IntMap a
958 = fromListWithKey (\k x y -> f x y) xs
960 -- | /O(n*min(n,W))/. Build a map from a list of key\/value pairs with a combining function. See also fromAscListWithKey'.
961 fromListWithKey :: (Key -> a -> a -> a) -> [(Key,a)] -> IntMap a
963 = foldlStrict ins empty xs
965 ins t (k,x) = insertWithKey f k x t
967 -- | /O(n*min(n,W))/. Build a map from a list of key\/value pairs where
968 -- the keys are in ascending order.
969 fromAscList :: [(Key,a)] -> IntMap a
973 -- | /O(n*min(n,W))/. Build a map from a list of key\/value pairs where
974 -- the keys are in ascending order, with a combining function on equal keys.
975 fromAscListWith :: (a -> a -> a) -> [(Key,a)] -> IntMap a
979 -- | /O(n*min(n,W))/. Build a map from a list of key\/value pairs where
980 -- the keys are in ascending order, with a combining function on equal keys.
981 fromAscListWithKey :: (Key -> a -> a -> a) -> [(Key,a)] -> IntMap a
982 fromAscListWithKey f xs
983 = fromListWithKey f xs
985 -- | /O(n*min(n,W))/. Build a map from a list of key\/value pairs where
986 -- the keys are in ascending order and all distinct.
987 fromDistinctAscList :: [(Key,a)] -> IntMap a
988 fromDistinctAscList xs
992 {--------------------------------------------------------------------
994 --------------------------------------------------------------------}
995 instance Eq a => Eq (IntMap a) where
996 t1 == t2 = equal t1 t2
997 t1 /= t2 = nequal t1 t2
999 equal :: Eq a => IntMap a -> IntMap a -> Bool
1000 equal (Bin p1 m1 l1 r1) (Bin p2 m2 l2 r2)
1001 = (m1 == m2) && (p1 == p2) && (equal l1 l2) && (equal r1 r2)
1002 equal (Tip kx x) (Tip ky y)
1003 = (kx == ky) && (x==y)
1004 equal Nil Nil = True
1007 nequal :: Eq a => IntMap a -> IntMap a -> Bool
1008 nequal (Bin p1 m1 l1 r1) (Bin p2 m2 l2 r2)
1009 = (m1 /= m2) || (p1 /= p2) || (nequal l1 l2) || (nequal r1 r2)
1010 nequal (Tip kx x) (Tip ky y)
1011 = (kx /= ky) || (x/=y)
1012 nequal Nil Nil = False
1015 {--------------------------------------------------------------------
1017 --------------------------------------------------------------------}
1019 instance Ord a => Ord (IntMap a) where
1020 compare m1 m2 = compare (toList m1) (toList m2)
1022 {--------------------------------------------------------------------
1024 --------------------------------------------------------------------}
1026 instance Functor IntMap where
1029 {--------------------------------------------------------------------
1031 --------------------------------------------------------------------}
1033 instance Show a => Show (IntMap a) where
1034 showsPrec d m = showParen (d > 10) $
1035 showString "fromList " . shows (toList m)
1037 showMap :: (Show a) => [(Key,a)] -> ShowS
1041 = showChar '{' . showElem x . showTail xs
1043 showTail [] = showChar '}'
1044 showTail (x:xs) = showChar ',' . showElem x . showTail xs
1046 showElem (k,x) = shows k . showString ":=" . shows x
1048 {--------------------------------------------------------------------
1050 --------------------------------------------------------------------}
1051 instance (Read e) => Read (IntMap e) where
1052 #ifdef __GLASGOW_HASKELL__
1053 readPrec = parens $ prec 10 $ do
1054 Ident "fromList" <- lexP
1056 return (fromList xs)
1058 readListPrec = readListPrecDefault
1060 readsPrec p = readParen (p > 10) $ \ r -> do
1061 ("fromList",s) <- lex r
1063 return (fromList xs,t)
1066 {--------------------------------------------------------------------
1068 --------------------------------------------------------------------}
1070 #include "Typeable.h"
1071 INSTANCE_TYPEABLE1(IntMap,intMapTc,"IntMap")
1073 {--------------------------------------------------------------------
1075 --------------------------------------------------------------------}
1076 -- | /O(n)/. Show the tree that implements the map. The tree is shown
1077 -- in a compressed, hanging format.
1078 showTree :: Show a => IntMap a -> String
1080 = showTreeWith True False s
1083 {- | /O(n)/. The expression (@'showTreeWith' hang wide map@) shows
1084 the tree that implements the map. If @hang@ is
1085 'True', a /hanging/ tree is shown otherwise a rotated tree is shown. If
1086 @wide@ is 'True', an extra wide version is shown.
1088 showTreeWith :: Show a => Bool -> Bool -> IntMap a -> String
1089 showTreeWith hang wide t
1090 | hang = (showsTreeHang wide [] t) ""
1091 | otherwise = (showsTree wide [] [] t) ""
1093 showsTree :: Show a => Bool -> [String] -> [String] -> IntMap a -> ShowS
1094 showsTree wide lbars rbars t
1097 -> showsTree wide (withBar rbars) (withEmpty rbars) r .
1098 showWide wide rbars .
1099 showsBars lbars . showString (showBin p m) . showString "\n" .
1100 showWide wide lbars .
1101 showsTree wide (withEmpty lbars) (withBar lbars) l
1103 -> showsBars lbars . showString " " . shows k . showString ":=" . shows x . showString "\n"
1104 Nil -> showsBars lbars . showString "|\n"
1106 showsTreeHang :: Show a => Bool -> [String] -> IntMap a -> ShowS
1107 showsTreeHang wide bars t
1110 -> showsBars bars . showString (showBin p m) . showString "\n" .
1111 showWide wide bars .
1112 showsTreeHang wide (withBar bars) l .
1113 showWide wide bars .
1114 showsTreeHang wide (withEmpty bars) r
1116 -> showsBars bars . showString " " . shows k . showString ":=" . shows x . showString "\n"
1117 Nil -> showsBars bars . showString "|\n"
1120 = "*" -- ++ show (p,m)
1123 | wide = showString (concat (reverse bars)) . showString "|\n"
1126 showsBars :: [String] -> ShowS
1130 _ -> showString (concat (reverse (tail bars))) . showString node
1133 withBar bars = "| ":bars
1134 withEmpty bars = " ":bars
1137 {--------------------------------------------------------------------
1139 --------------------------------------------------------------------}
1140 {--------------------------------------------------------------------
1142 --------------------------------------------------------------------}
1143 join :: Prefix -> IntMap a -> Prefix -> IntMap a -> IntMap a
1145 | zero p1 m = Bin p m t1 t2
1146 | otherwise = Bin p m t2 t1
1148 m = branchMask p1 p2
1151 {--------------------------------------------------------------------
1152 @bin@ assures that we never have empty trees within a tree.
1153 --------------------------------------------------------------------}
1154 bin :: Prefix -> Mask -> IntMap a -> IntMap a -> IntMap a
1157 bin p m l r = Bin p m l r
1160 {--------------------------------------------------------------------
1161 Endian independent bit twiddling
1162 --------------------------------------------------------------------}
1163 zero :: Key -> Mask -> Bool
1165 = (natFromInt i) .&. (natFromInt m) == 0
1167 nomatch,match :: Key -> Prefix -> Mask -> Bool
1174 mask :: Key -> Mask -> Prefix
1176 = maskW (natFromInt i) (natFromInt m)
1179 zeroN :: Nat -> Nat -> Bool
1180 zeroN i m = (i .&. m) == 0
1182 {--------------------------------------------------------------------
1183 Big endian operations
1184 --------------------------------------------------------------------}
1185 maskW :: Nat -> Nat -> Prefix
1187 = intFromNat (i .&. (complement (m-1) `xor` m))
1189 shorter :: Mask -> Mask -> Bool
1191 = (natFromInt m1) > (natFromInt m2)
1193 branchMask :: Prefix -> Prefix -> Mask
1195 = intFromNat (highestBitMask (natFromInt p1 `xor` natFromInt p2))
1197 {----------------------------------------------------------------------
1198 Finding the highest bit (mask) in a word [x] can be done efficiently in
1200 * convert to a floating point value and the mantissa tells us the
1201 [log2(x)] that corresponds with the highest bit position. The mantissa
1202 is retrieved either via the standard C function [frexp] or by some bit
1203 twiddling on IEEE compatible numbers (float). Note that one needs to
1204 use at least [double] precision for an accurate mantissa of 32 bit
1206 * use bit twiddling, a logarithmic sequence of bitwise or's and shifts (bit).
1207 * use processor specific assembler instruction (asm).
1209 The most portable way would be [bit], but is it efficient enough?
1210 I have measured the cycle counts of the different methods on an AMD
1211 Athlon-XP 1800 (~ Pentium III 1.8Ghz) using the RDTSC instruction:
1213 highestBitMask: method cycles
1220 highestBit: method cycles
1227 Wow, the bit twiddling is on today's RISC like machines even faster
1228 than a single CISC instruction (BSR)!
1229 ----------------------------------------------------------------------}
1231 {----------------------------------------------------------------------
1232 [highestBitMask] returns a word where only the highest bit is set.
1233 It is found by first setting all bits in lower positions than the
1234 highest bit and than taking an exclusive or with the original value.
1235 Allthough the function may look expensive, GHC compiles this into
1236 excellent C code that subsequently compiled into highly efficient
1237 machine code. The algorithm is derived from Jorg Arndt's FXT library.
1238 ----------------------------------------------------------------------}
1239 highestBitMask :: Nat -> Nat
1241 = case (x .|. shiftRL x 1) of
1242 x -> case (x .|. shiftRL x 2) of
1243 x -> case (x .|. shiftRL x 4) of
1244 x -> case (x .|. shiftRL x 8) of
1245 x -> case (x .|. shiftRL x 16) of
1246 x -> case (x .|. shiftRL x 32) of -- for 64 bit platforms
1247 x -> (x `xor` (shiftRL x 1))
1250 {--------------------------------------------------------------------
1252 --------------------------------------------------------------------}
1256 (x:xx) -> let z' = f z x in seq z' (foldlStrict f z' xx)
1259 {--------------------------------------------------------------------
1261 --------------------------------------------------------------------}
1262 testTree :: [Int] -> IntMap Int
1263 testTree xs = fromList [(x,x*x*30696 `mod` 65521) | x <- xs]
1264 test1 = testTree [1..20]
1265 test2 = testTree [30,29..10]
1266 test3 = testTree [1,4,6,89,2323,53,43,234,5,79,12,9,24,9,8,423,8,42,4,8,9,3]
1268 {--------------------------------------------------------------------
1270 --------------------------------------------------------------------}
1275 { configMaxTest = 500
1276 , configMaxFail = 5000
1277 , configSize = \n -> (div n 2 + 3)
1278 , configEvery = \n args -> let s = show n in s ++ [ '\b' | _ <- s ]
1282 {--------------------------------------------------------------------
1283 Arbitrary, reasonably balanced trees
1284 --------------------------------------------------------------------}
1285 instance Arbitrary a => Arbitrary (IntMap a) where
1286 arbitrary = do{ ks <- arbitrary
1287 ; xs <- mapM (\k -> do{ x <- arbitrary; return (k,x)}) ks
1288 ; return (fromList xs)
1292 {--------------------------------------------------------------------
1293 Single, Insert, Delete
1294 --------------------------------------------------------------------}
1295 prop_Single :: Key -> Int -> Bool
1297 = (insert k x empty == singleton k x)
1299 prop_InsertDelete :: Key -> Int -> IntMap Int -> Property
1300 prop_InsertDelete k x t
1301 = not (member k t) ==> delete k (insert k x t) == t
1303 prop_UpdateDelete :: Key -> IntMap Int -> Bool
1304 prop_UpdateDelete k t
1305 = update (const Nothing) k t == delete k t
1308 {--------------------------------------------------------------------
1310 --------------------------------------------------------------------}
1311 prop_UnionInsert :: Key -> Int -> IntMap Int -> Bool
1312 prop_UnionInsert k x t
1313 = union (singleton k x) t == insert k x t
1315 prop_UnionAssoc :: IntMap Int -> IntMap Int -> IntMap Int -> Bool
1316 prop_UnionAssoc t1 t2 t3
1317 = union t1 (union t2 t3) == union (union t1 t2) t3
1319 prop_UnionComm :: IntMap Int -> IntMap Int -> Bool
1320 prop_UnionComm t1 t2
1321 = (union t1 t2 == unionWith (\x y -> y) t2 t1)
1324 prop_Diff :: [(Key,Int)] -> [(Key,Int)] -> Bool
1326 = List.sort (keys (difference (fromListWith (+) xs) (fromListWith (+) ys)))
1327 == List.sort ((List.\\) (nub (Prelude.map fst xs)) (nub (Prelude.map fst ys)))
1329 prop_Int :: [(Key,Int)] -> [(Key,Int)] -> Bool
1331 = List.sort (keys (intersection (fromListWith (+) xs) (fromListWith (+) ys)))
1332 == List.sort (nub ((List.intersect) (Prelude.map fst xs) (Prelude.map fst ys)))
1334 {--------------------------------------------------------------------
1336 --------------------------------------------------------------------}
1338 = forAll (choose (5,100)) $ \n ->
1339 let xs = [(x,()) | x <- [0..n::Int]]
1340 in fromAscList xs == fromList xs
1342 prop_List :: [Key] -> Bool
1344 = (sort (nub xs) == [x | (x,()) <- toAscList (fromList [(x,()) | x <- xs])])