1 -----------------------------------------------------------------------------
3 -- Module : Data.FiniteMap
4 -- Copyright : (c) The University of Glasgow 2001
5 -- License : BSD-style (see the file libraries/base/LICENSE)
7 -- Maintainer : libraries@haskell.org
8 -- Stability : provisional
9 -- Portability : portable
11 -- NOTE: Data.FiniteMap is DEPRECATED, please use "Data.Map" instead.
13 -- A finite map implementation, derived from the paper:
14 -- /Efficient sets: a balancing act/, S. Adams,
15 -- Journal of functional programming 3(4) Oct 1993, pp553-562
17 -----------------------------------------------------------------------------
19 -- ToDo: clean up, remove the COMPILING_GHC stuff.
21 -- The code is SPECIALIZEd to various highly-desirable types (e.g., Id)
22 -- near the end (only \tr{#ifdef COMPILING_GHC}).
25 #include "HsVersions.h"
26 #define IF_NOT_GHC(a) {--}
28 #define ASSERT(e) {--}
29 #define IF_NOT_GHC(a) a
31 #define _tagCmp compare
37 #if defined(COMPILING_GHC) && defined(DEBUG_FINITEMAPS)/* NB NB NB */
38 #define OUTPUTABLE_key , Outputable key
40 #define OUTPUTABLE_key {--}
44 {-# DEPRECATED "Please use Data.Map instead." #-}
46 -- * The @FiniteMap@ type
47 FiniteMap, -- abstract type
50 emptyFM, unitFM, listToFM,
52 -- * Lookup operations
53 lookupFM, lookupWithDefaultFM,
62 -- * Deleting elements
63 IF_NOT_GHC(delFromFM COMMA)
70 -- * Extracting information
71 fmToList, keysFM, eltsFM,
77 IF_NOT_GHC(intersectFM COMMA)
78 IF_NOT_GHC(intersectFM_C COMMA)
79 IF_NOT_GHC(mapFM COMMA filterFM COMMA)
81 foldFM_GE, fmToList_GE, keysFM_GE, eltsFM_GE,
82 foldFM_LE, fmToList_LE, keysFM_LE, eltsFM_LE,
91 import Prelude -- necessary to get dependencies right
93 import Data.Maybe ( isJust )
94 #ifdef __GLASGOW_HASKELL__
97 import Data.Generics.Basics
98 import Data.Generics.Instances
110 import Bag ( foldBag )
112 # if ! OMIT_NATIVE_CODEGEN
115 # define IF_NCG(a) {--}
119 -- SIGH: but we use unboxed "sizes"...
120 #if __GLASGOW_HASKELL__
121 #define IF_GHC(a,b) a
123 #define IF_GHC(a,b) b
128 -- ---------------------------------------------------------------------------
129 -- The signature of the module
131 -- | An empty 'FiniteMap'.
132 emptyFM :: FiniteMap key elt
134 -- | A 'FiniteMap' containing a single mapping
135 unitFM :: key -> elt -> FiniteMap key elt
137 -- | Makes a 'FiniteMap' from a list of @(key,value)@ pairs. In the
138 -- case of duplicates, the last is taken
139 listToFM :: (Ord key OUTPUTABLE_key) => [(key,elt)] -> FiniteMap key elt
142 bagToFM :: (Ord key OUTPUTABLE_key) => Bag (key,elt) -> FiniteMap key elt
143 -- In the case of duplicates, who knows which is taken
146 -- ADDING AND DELETING
148 -- | Adds an element to a 'FiniteMap'. Any previous mapping with the same
149 -- key is overwritten.
150 addToFM :: (Ord key OUTPUTABLE_key) => FiniteMap key elt -> key -> elt -> FiniteMap key elt
152 -- | Adds a list of elements to a 'FiniteMap', in the order given in
153 -- the list. Overwrites previous mappings.
154 addListToFM :: (Ord key OUTPUTABLE_key) => FiniteMap key elt -> [(key,elt)] -> FiniteMap key elt
156 -- Combines with previous binding
157 -- In the combining function, the first argument is the "old" element,
158 -- while the second is the "new" one.
160 -- | Adds an element to a 'FiniteMap'. If there is already an element
161 -- with the same key, then the specified combination function is used
162 -- to calculate the new value. The already present element is passed as
163 -- the first argument and the new element to add as second.
164 addToFM_C :: (Ord key OUTPUTABLE_key) => (elt -> elt -> elt)
165 -> FiniteMap key elt -> key -> elt
168 -- | A list version of 'addToFM_C'. The elements are added in the
169 -- order given in the list.
170 addListToFM_C :: (Ord key OUTPUTABLE_key) => (elt -> elt -> elt)
171 -> FiniteMap key elt -> [(key,elt)]
174 -- | Deletes an element from a 'FiniteMap'. If there is no element with
175 -- the specified key, then the original 'FiniteMap' is returned.
176 delFromFM :: (Ord key OUTPUTABLE_key) => FiniteMap key elt -> key -> FiniteMap key elt
178 -- | List version of 'delFromFM'.
179 delListFromFM :: (Ord key OUTPUTABLE_key) => FiniteMap key elt -> [key] -> FiniteMap key elt
181 -- | Combine two 'FiniteMap's. Mappings in the second argument shadow
182 -- those in the first.
183 plusFM :: (Ord key OUTPUTABLE_key) => FiniteMap key elt -> FiniteMap key elt
186 -- | Combine two 'FiniteMap's. The specified combination function is
187 -- used to calculate the new value when there are two elements with
189 plusFM_C :: (Ord key OUTPUTABLE_key) => (elt -> elt -> elt)
190 -> FiniteMap key elt -> FiniteMap key elt -> FiniteMap key elt
192 -- | @(minusFM a1 a2)@ deletes from @a1@ any mappings which are bound in @a2@
193 minusFM :: (Ord key OUTPUTABLE_key) => FiniteMap key elt1 -> FiniteMap key elt2 -> FiniteMap key elt1
195 -- | @(intersectFM a1 a2)@ returns a new 'FiniteMap' containing
196 -- mappings from @a1@ for which @a2@ also has a mapping with the same
198 intersectFM :: (Ord key OUTPUTABLE_key) => FiniteMap key elt -> FiniteMap key elt -> FiniteMap key elt
200 -- | Returns the intersection of two mappings, using the specified
201 -- combination function to combine values.
202 intersectFM_C :: (Ord key OUTPUTABLE_key) => (elt1 -> elt2 -> elt3)
203 -> FiniteMap key elt1 -> FiniteMap key elt2 -> FiniteMap key elt3
205 -- MAPPING, FOLDING, FILTERING
206 foldFM :: (key -> elt -> a -> a) -> a -> FiniteMap key elt -> a
207 mapFM :: (key -> elt1 -> elt2) -> FiniteMap key elt1 -> FiniteMap key elt2
208 filterFM :: (Ord key OUTPUTABLE_key) => (key -> elt -> Bool)
209 -> FiniteMap key elt -> FiniteMap key elt
212 sizeFM :: FiniteMap key elt -> Int
213 isEmptyFM :: FiniteMap key elt -> Bool
215 -- | Returns 'True' if the specified @key@ has a mapping in this
216 -- 'FiniteMap', or 'False' otherwise.
217 elemFM :: (Ord key OUTPUTABLE_key) => key -> FiniteMap key elt -> Bool
219 -- | Looks up a key in a 'FiniteMap', returning @'Just' v@ if the key
220 -- was found with value @v@, or 'Nothing' otherwise.
221 lookupFM :: (Ord key OUTPUTABLE_key) => FiniteMap key elt -> key -> Maybe elt
223 -- | Looks up a key in a 'FiniteMap', returning @elt@ if the specified
224 -- @key@ was not found.
226 :: (Ord key OUTPUTABLE_key) => FiniteMap key elt -> elt -> key -> elt
227 -- lookupWithDefaultFM supplies a "default" elt
228 -- to return for an unmapped key
232 -- | Convert a 'FiniteMap' to a @[(key, elt)]@ sorted by 'Ord' key
234 fmToList :: FiniteMap key elt -> [(key,elt)]
236 -- | Extract the keys from a 'FiniteMap', in the order of the keys, so
238 -- > keysFM == map fst . fmToList
240 keysFM :: FiniteMap key elt -> [key]
242 -- | Extract the elements from a 'FiniteMap', in the order of the keys, so
244 -- > eltsFM == map snd . fmToList
246 eltsFM :: FiniteMap key elt -> [elt]
248 -- ---------------------------------------------------------------------------
249 -- The @FiniteMap@ data type, and building of same
251 -- Invariants about @FiniteMap@:
253 -- * all keys in a FiniteMap are distinct
255 -- * all keys in left subtree are $<$ key in Branch and
256 -- all keys in right subtree are $>$ key in Branch
258 -- * size field of a Branch gives number of Branch nodes in the tree
260 -- * size of left subtree is differs from size of right subtree by a
261 -- factor of at most \tr{sIZE_RATIO}
263 -- | A mapping from @key@s to @elt@s.
264 data FiniteMap key elt
266 | Branch key elt -- Key and elt stored here
267 IF_GHC(Int#,Int{-STRICT-}) -- Size >= 1
268 (FiniteMap key elt) -- Children
275 = Branch bottom bottom IF_GHC(0#,0) bottom bottom
277 bottom = panic "emptyFM"
280 -- #define EmptyFM (Branch _ _ IF_GHC(0#,0) _ _)
282 unitFM key elt = Branch key elt IF_GHC(1#,1) emptyFM emptyFM
284 listToFM = addListToFM emptyFM
287 bagToFM = foldBag plusFM (\ (k,v) -> unitFM k v) emptyFM
290 instance (Show k, Show e) => Show (FiniteMap k e) where
291 showsPrec p m = showsPrec p (fmToList m)
293 instance Functor (FiniteMap k) where
294 fmap f = mapFM (const f)
296 #if __GLASGOW_HASKELL__
298 #include "Typeable.h"
299 INSTANCE_TYPEABLE2(FiniteMap,arrayTc,"FiniteMap")
301 -- This instance preserves data abstraction at the cost of inefficiency.
302 -- We omit reflection services for the sake of data abstraction.
304 instance (Data a, Data b, Ord a) => Data (FiniteMap a b) where
305 gfoldl f z fm = z listToFM `f` (fmToList fm)
306 toConstr _ = error "toConstr"
307 gunfold _ _ = error "gunfold"
308 dataTypeOf _ = mkNorepType "Data.FiniteMap.FiniteMap"
313 -- ---------------------------------------------------------------------------
314 -- Adding to and deleting from @FiniteMaps@
316 addToFM fm key elt = addToFM_C (\ old new -> new) fm key elt
318 addToFM_C combiner EmptyFM key elt = unitFM key elt
319 addToFM_C combiner (Branch key elt size fm_l fm_r) new_key new_elt
320 #ifdef __GLASGOW_HASKELL__
321 = case _tagCmp new_key key of
322 _LT -> mkBalBranch key elt (addToFM_C combiner fm_l new_key new_elt) fm_r
323 _GT -> mkBalBranch key elt fm_l (addToFM_C combiner fm_r new_key new_elt)
324 _EQ -> Branch new_key (combiner elt new_elt) size fm_l fm_r
326 | new_key < key = mkBalBranch key elt (addToFM_C combiner fm_l new_key new_elt) fm_r
327 | new_key > key = mkBalBranch key elt fm_l (addToFM_C combiner fm_r new_key new_elt)
328 | otherwise = Branch new_key (combiner elt new_elt) size fm_l fm_r
331 addListToFM fm key_elt_pairs = addListToFM_C (\ old new -> new) fm key_elt_pairs
333 addListToFM_C combiner fm key_elt_pairs
334 = foldl add fm key_elt_pairs -- foldl adds from the left
336 add fmap (key,elt) = addToFM_C combiner fmap key elt
339 delFromFM EmptyFM del_key = emptyFM
340 delFromFM (Branch key elt size fm_l fm_r) del_key
341 #if __GLASGOW_HASKELL__
342 = case _tagCmp del_key key of
343 _GT -> mkBalBranch key elt fm_l (delFromFM fm_r del_key)
344 _LT -> mkBalBranch key elt (delFromFM fm_l del_key) fm_r
345 _EQ -> glueBal fm_l fm_r
348 = mkBalBranch key elt fm_l (delFromFM fm_r del_key)
351 = mkBalBranch key elt (delFromFM fm_l del_key) fm_r
357 delListFromFM fm keys = foldl delFromFM fm keys
359 -- ---------------------------------------------------------------------------
360 -- Combining @FiniteMaps@
362 plusFM_C combiner EmptyFM fm2 = fm2
363 plusFM_C combiner fm1 EmptyFM = fm1
364 plusFM_C combiner fm1 (Branch split_key elt2 _ left right)
365 = mkVBalBranch split_key new_elt
366 (plusFM_C combiner lts left)
367 (plusFM_C combiner gts right)
369 lts = splitLT fm1 split_key
370 gts = splitGT fm1 split_key
371 new_elt = case lookupFM fm1 split_key of
373 Just elt1 -> combiner elt1 elt2
375 -- It's worth doing plusFM specially, because we don't need
376 -- to do the lookup in fm1.
378 plusFM EmptyFM fm2 = fm2
379 plusFM fm1 EmptyFM = fm1
380 plusFM fm1 (Branch split_key elt1 _ left right)
381 = mkVBalBranch split_key elt1 (plusFM lts left) (plusFM gts right)
383 lts = splitLT fm1 split_key
384 gts = splitGT fm1 split_key
386 minusFM EmptyFM fm2 = emptyFM
387 minusFM fm1 EmptyFM = fm1
388 minusFM fm1 (Branch split_key elt _ left right)
389 = glueVBal (minusFM lts left) (minusFM gts right)
390 -- The two can be way different, so we need glueVBal
392 lts = splitLT fm1 split_key -- NB gt and lt, so the equal ones
393 gts = splitGT fm1 split_key -- are not in either.
395 intersectFM fm1 fm2 = intersectFM_C (\ left right -> right) fm1 fm2
397 intersectFM_C combiner fm1 EmptyFM = emptyFM
398 intersectFM_C combiner EmptyFM fm2 = emptyFM
399 intersectFM_C combiner fm1 (Branch split_key elt2 _ left right)
401 | isJust maybe_elt1 -- split_elt *is* in intersection
402 = mkVBalBranch split_key (combiner elt1 elt2) (intersectFM_C combiner lts left)
403 (intersectFM_C combiner gts right)
405 | otherwise -- split_elt is *not* in intersection
406 = glueVBal (intersectFM_C combiner lts left) (intersectFM_C combiner gts right)
409 lts = splitLT fm1 split_key -- NB gt and lt, so the equal ones
410 gts = splitGT fm1 split_key -- are not in either.
412 maybe_elt1 = lookupFM fm1 split_key
413 Just elt1 = maybe_elt1
416 -- ---------------------------------------------------------------------------
417 -- Mapping, folding, and filtering with @FiniteMaps@
419 foldFM k z EmptyFM = z
420 foldFM k z (Branch key elt _ fm_l fm_r)
421 = foldFM k (k key elt (foldFM k z fm_r)) fm_l
423 mapFM f EmptyFM = emptyFM
424 mapFM f (Branch key elt size fm_l fm_r)
425 = Branch key (f key elt) size (mapFM f fm_l) (mapFM f fm_r)
427 filterFM p EmptyFM = emptyFM
428 filterFM p (Branch key elt _ fm_l fm_r)
429 | p key elt -- Keep the item
430 = mkVBalBranch key elt (filterFM p fm_l) (filterFM p fm_r)
432 | otherwise -- Drop the item
433 = glueVBal (filterFM p fm_l) (filterFM p fm_r)
436 -- ---------------------------------------------------------------------------
437 -- Interrogating @FiniteMaps@
439 --{-# INLINE sizeFM #-}
441 sizeFM (Branch _ _ size _ _) = IF_GHC(I# size, size)
443 isEmptyFM fm = sizeFM fm == 0
445 lookupFM EmptyFM key = Nothing
446 lookupFM (Branch key elt _ fm_l fm_r) key_to_find
447 #if __GLASGOW_HASKELL__
448 = case _tagCmp key_to_find key of
449 _LT -> lookupFM fm_l key_to_find
450 _GT -> lookupFM fm_r key_to_find
453 | key_to_find < key = lookupFM fm_l key_to_find
454 | key_to_find > key = lookupFM fm_r key_to_find
455 | otherwise = Just elt
459 = case (lookupFM fm key) of { Nothing -> False; Just elt -> True }
461 lookupWithDefaultFM fm deflt key
462 = case (lookupFM fm key) of { Nothing -> deflt; Just elt -> elt }
465 -- ---------------------------------------------------------------------------
466 -- Listifying @FiniteMaps@
468 fmToList fm = foldFM (\ key elt rest -> (key,elt) : rest) [] fm
469 keysFM fm = foldFM (\ key elt rest -> key : rest) [] fm
470 eltsFM fm = foldFM (\ key elt rest -> elt : rest) [] fm
473 -- ---------------------------------------------------------------------------
474 -- Bulk operations on all keys >= or <= a certain threshold
476 -- | Fold through all elements greater than or equal to the supplied key,
477 -- in increasing order.
478 foldFM_GE :: Ord key => (key -> elt -> a -> a) -> a -> key ->
479 FiniteMap key elt -> a
481 foldFM_GE k z fr EmptyFM = z
482 foldFM_GE k z fr (Branch key elt _ fm_l fm_r)
483 | key >= fr = foldFM_GE k (k key elt (foldFM_GE k z fr fm_r)) fr fm_l
484 | otherwise = foldFM_GE k z fr fm_r
486 -- | List elements greater than or equal to the supplied key, in increasing
488 fmToList_GE :: Ord key => FiniteMap key elt -> key -> [(key,elt)]
489 fmToList_GE fm fr = foldFM_GE (\ key elt rest -> (key,elt) : rest) [] fr fm
491 -- | List keys greater than or equal to the supplied key, in increasing order
492 keysFM_GE :: Ord key => FiniteMap key elt -> key -> [key]
493 keysFM_GE fm fr = foldFM_GE (\ key elt rest -> key : rest) [] fr fm
495 -- | List elements corresponding to keys greater than or equal to the supplied
496 -- key, in increasing order of key.
497 eltsFM_GE :: Ord key => FiniteMap key elt -> key -> [elt]
498 eltsFM_GE fm fr = foldFM_GE (\ key elt rest -> elt : rest) [] fr fm
500 -- | Fold through all elements less than or equal to the supplied key,
501 -- in decreasing order.
502 foldFM_LE :: Ord key => (key -> elt -> a -> a) -> a -> key ->
503 FiniteMap key elt -> a
504 foldFM_LE k z fr EmptyFM = z
505 foldFM_LE k z fr (Branch key elt _ fm_l fm_r)
506 | key <= fr = foldFM_LE k (k key elt (foldFM_LE k z fr fm_l)) fr fm_r
507 | otherwise = foldFM_LE k z fr fm_l
509 -- | List elements greater than or equal to the supplied key, in decreasing
511 fmToList_LE :: Ord key => FiniteMap key elt -> key -> [(key,elt)]
512 fmToList_LE fm fr = foldFM_LE (\ key elt rest -> (key,elt) : rest) [] fr fm
514 -- | List keys greater than or equal to the supplied key, in decreasing order
515 keysFM_LE :: Ord key => FiniteMap key elt -> key -> [key]
516 keysFM_LE fm fr = foldFM_LE (\ key elt rest -> key : rest) [] fr fm
518 -- | List elements corresponding to keys greater than or equal to the supplied
519 -- key, in decreasing order of key.
520 eltsFM_LE :: Ord key => FiniteMap key elt -> key -> [elt]
521 eltsFM_LE fm fr = foldFM_LE (\ key elt rest -> elt : rest) [] fr fm
523 -- ---------------------------------------------------------------------------
524 -- Getting minimum and maximum key out.
525 -- ---------------------------------------------------------------------------
527 -- | Extract minimum key, or Nothing if the map is empty.
528 minFM :: Ord key => FiniteMap key elt -> Maybe key
529 minFM EmptyFM = Nothing
530 minFM (Branch key _ _ fm_l _) =
533 Just key1 -> Just key1
535 -- | Extract maximum key, or Nothing if the map is empty.
536 maxFM :: Ord key => FiniteMap key elt -> Maybe key
537 maxFM EmptyFM = Nothing
538 maxFM (Branch key _ _ _ fm_r) =
541 Just key1 -> Just key1
544 -- ---------------------------------------------------------------------------
545 -- The implementation of balancing
547 -- Basic construction of a @FiniteMap@:
549 -- @mkBranch@ simply gets the size component right. This is the ONLY
550 -- (non-trivial) place the Branch object is built, so the ASSERTion
551 -- recursively checks consistency. (The trivial use of Branch is in
557 mkBranch :: (Ord key OUTPUTABLE_key) -- Used for the assertion checking only
560 -> FiniteMap key elt -> FiniteMap key elt
563 mkBranch which key elt fm_l fm_r
564 = --ASSERT( left_ok && right_ok && balance_ok )
565 #if defined(COMPILING_GHC) && defined(DEBUG_FINITEMAPS)
566 if not ( left_ok && right_ok && balance_ok ) then
567 pprPanic ("mkBranch:"++show which) (ppAboves [ppr PprDebug [left_ok, right_ok, balance_ok],
574 result = Branch key elt (unbox (1 + left_size + right_size)) fm_l fm_r
576 -- if sizeFM result <= 8 then
579 -- pprTrace ("mkBranch:"++(show which)) (ppr PprDebug result) (
583 left_ok = case fm_l of
585 Branch left_key _ _ _ _ -> let
586 biggest_left_key = fst (findMax fm_l)
588 biggest_left_key < key
589 right_ok = case fm_r of
591 Branch right_key _ _ _ _ -> let
592 smallest_right_key = fst (findMin fm_r)
594 key < smallest_right_key
595 balance_ok = True -- sigh
598 = -- Both subtrees have one or no elements...
599 (left_size + right_size <= 1)
600 -- NO || left_size == 0 -- ???
601 -- NO || right_size == 0 -- ???
602 -- ... or the number of elements in a subtree does not exceed
603 -- sIZE_RATIO times the number of elements in the other subtree
604 || (left_size * sIZE_RATIO >= right_size &&
605 right_size * sIZE_RATIO >= left_size)
608 left_size = sizeFM fm_l
609 right_size = sizeFM fm_r
611 #if __GLASGOW_HASKELL__
613 unbox (I# size) = size
620 -- ---------------------------------------------------------------------------
621 -- {\em Balanced} construction of a @FiniteMap@
623 -- @mkBalBranch@ rebalances, assuming that the subtrees aren't too far
626 mkBalBranch :: (Ord key OUTPUTABLE_key)
628 -> FiniteMap key elt -> FiniteMap key elt
631 mkBalBranch key elt fm_L fm_R
633 | size_l + size_r < 2
634 = mkBranch 1{-which-} key elt fm_L fm_R
636 | size_r > sIZE_RATIO * size_l -- Right tree too big
638 Branch _ _ _ fm_rl fm_rr
639 | sizeFM fm_rl < 2 * sizeFM fm_rr -> single_L fm_L fm_R
640 | otherwise -> double_L fm_L fm_R
641 -- Other case impossible
643 | size_l > sIZE_RATIO * size_r -- Left tree too big
645 Branch _ _ _ fm_ll fm_lr
646 | sizeFM fm_lr < 2 * sizeFM fm_ll -> single_R fm_L fm_R
647 | otherwise -> double_R fm_L fm_R
648 -- Other case impossible
650 | otherwise -- No imbalance
651 = mkBranch 2{-which-} key elt fm_L fm_R
657 single_L fm_l (Branch key_r elt_r _ fm_rl fm_rr)
658 = mkBranch 3{-which-} key_r elt_r (mkBranch 4{-which-} key elt fm_l fm_rl) fm_rr
660 double_L fm_l (Branch key_r elt_r _ (Branch key_rl elt_rl _ fm_rll fm_rlr) fm_rr)
661 = mkBranch 5{-which-} key_rl elt_rl (mkBranch 6{-which-} key elt fm_l fm_rll)
662 (mkBranch 7{-which-} key_r elt_r fm_rlr fm_rr)
664 single_R (Branch key_l elt_l _ fm_ll fm_lr) fm_r
665 = mkBranch 8{-which-} key_l elt_l fm_ll (mkBranch 9{-which-} key elt fm_lr fm_r)
667 double_R (Branch key_l elt_l _ fm_ll (Branch key_lr elt_lr _ fm_lrl fm_lrr)) fm_r
668 = mkBranch 10{-which-} key_lr elt_lr (mkBranch 11{-which-} key_l elt_l fm_ll fm_lrl)
669 (mkBranch 12{-which-} key elt fm_lrr fm_r)
672 mkVBalBranch :: (Ord key OUTPUTABLE_key)
674 -> FiniteMap key elt -> FiniteMap key elt
677 -- Assert: in any call to (mkVBalBranch_C comb key elt l r),
678 -- (a) all keys in l are < all keys in r
679 -- (b) all keys in l are < key
680 -- (c) all keys in r are > key
682 mkVBalBranch key elt EmptyFM fm_r = addToFM fm_r key elt
683 mkVBalBranch key elt fm_l EmptyFM = addToFM fm_l key elt
685 mkVBalBranch key elt fm_l@(Branch key_l elt_l _ fm_ll fm_lr)
686 fm_r@(Branch key_r elt_r _ fm_rl fm_rr)
687 | sIZE_RATIO * size_l < size_r
688 = mkBalBranch key_r elt_r (mkVBalBranch key elt fm_l fm_rl) fm_rr
690 | sIZE_RATIO * size_r < size_l
691 = mkBalBranch key_l elt_l fm_ll (mkVBalBranch key elt fm_lr fm_r)
694 = mkBranch 13{-which-} key elt fm_l fm_r
700 -- ---------------------------------------------------------------------------
701 -- Gluing two trees together
703 -- @glueBal@ assumes its two arguments aren't too far out of whack, just
704 -- like @mkBalBranch@. But: all keys in first arg are $<$ all keys in
707 glueBal :: (Ord key OUTPUTABLE_key)
708 => FiniteMap key elt -> FiniteMap key elt
711 glueBal EmptyFM fm2 = fm2
712 glueBal fm1 EmptyFM = fm1
714 -- The case analysis here (absent in Adams' program) is really to deal
715 -- with the case where fm2 is a singleton. Then deleting the minimum means
716 -- we pass an empty tree to mkBalBranch, which breaks its invariant.
717 | sizeFM fm2 > sizeFM fm1
718 = mkBalBranch mid_key2 mid_elt2 fm1 (deleteMin fm2)
721 = mkBalBranch mid_key1 mid_elt1 (deleteMax fm1) fm2
723 (mid_key1, mid_elt1) = findMax fm1
724 (mid_key2, mid_elt2) = findMin fm2
726 -- @glueVBal@ copes with arguments which can be of any size.
727 -- But: all keys in first arg are $<$ all keys in second.
729 glueVBal :: (Ord key OUTPUTABLE_key)
730 => FiniteMap key elt -> FiniteMap key elt
733 glueVBal EmptyFM fm2 = fm2
734 glueVBal fm1 EmptyFM = fm1
735 glueVBal fm_l@(Branch key_l elt_l _ fm_ll fm_lr)
736 fm_r@(Branch key_r elt_r _ fm_rl fm_rr)
737 | sIZE_RATIO * size_l < size_r
738 = mkBalBranch key_r elt_r (glueVBal fm_l fm_rl) fm_rr
740 | sIZE_RATIO * size_r < size_l
741 = mkBalBranch key_l elt_l fm_ll (glueVBal fm_lr fm_r)
743 | otherwise -- We now need the same two cases as in glueBal above.
750 -- ---------------------------------------------------------------------------
753 splitLT, splitGT :: (Ord key OUTPUTABLE_key) => FiniteMap key elt -> key -> FiniteMap key elt
755 -- splitLT fm split_key = fm restricted to keys < split_key
756 -- splitGT fm split_key = fm restricted to keys > split_key
758 splitLT EmptyFM split_key = emptyFM
759 splitLT (Branch key elt _ fm_l fm_r) split_key
760 #if __GLASGOW_HASKELL__
761 = case _tagCmp split_key key of
762 _LT -> splitLT fm_l split_key
763 _GT -> mkVBalBranch key elt fm_l (splitLT fm_r split_key)
766 | split_key < key = splitLT fm_l split_key
767 | split_key > key = mkVBalBranch key elt fm_l (splitLT fm_r split_key)
771 splitGT EmptyFM split_key = emptyFM
772 splitGT (Branch key elt _ fm_l fm_r) split_key
773 #if __GLASGOW_HASKELL__
774 = case _tagCmp split_key key of
775 _GT -> splitGT fm_r split_key
776 _LT -> mkVBalBranch key elt (splitGT fm_l split_key) fm_r
779 | split_key > key = splitGT fm_r split_key
780 | split_key < key = mkVBalBranch key elt (splitGT fm_l split_key) fm_r
784 findMin :: FiniteMap key elt -> (key,elt)
785 findMin (Branch key elt _ EmptyFM _) = (key,elt)
786 findMin (Branch key elt _ fm_l _) = findMin fm_l
788 deleteMin :: (Ord key OUTPUTABLE_key) => FiniteMap key elt -> FiniteMap key elt
789 deleteMin (Branch key elt _ EmptyFM fm_r) = fm_r
790 deleteMin (Branch key elt _ fm_l fm_r) = mkBalBranch key elt (deleteMin fm_l) fm_r
792 findMax :: FiniteMap key elt -> (key,elt)
793 findMax (Branch key elt _ _ EmptyFM) = (key,elt)
794 findMax (Branch key elt _ _ fm_r) = findMax fm_r
796 deleteMax :: (Ord key OUTPUTABLE_key) => FiniteMap key elt -> FiniteMap key elt
797 deleteMax (Branch key elt _ fm_l EmptyFM) = fm_l
798 deleteMax (Branch key elt _ fm_l fm_r) = mkBalBranch key elt fm_l (deleteMax fm_r)
801 -- ---------------------------------------------------------------------------
804 #if defined(COMPILING_GHC) && defined(DEBUG_FINITEMAPS)
806 instance (Outputable key) => Outputable (FiniteMap key elt) where
807 ppr sty fm = pprX sty fm
809 pprX sty EmptyFM = ppChar '!'
810 pprX sty (Branch key elt sz fm_l fm_r)
811 = ppBesides [ppLparen, pprX sty fm_l, ppSP,
812 ppr sty key, ppSP, ppInt (IF_GHC(I# sz, sz)), ppSP,
813 pprX sty fm_r, ppRparen]
816 #ifndef COMPILING_GHC
817 instance (Eq key, Eq elt) => Eq (FiniteMap key elt) where
818 fm_1 == fm_2 = (sizeFM fm_1 == sizeFM fm_2) && -- quick test
819 (fmToList fm_1 == fmToList fm_2)
821 {- NO: not clear what The Right Thing to do is:
822 instance (Ord key, Ord elt) => Ord (FiniteMap key elt) where
823 fm_1 <= fm_2 = (sizeFM fm_1 <= sizeFM fm_2) && -- quick test
824 (fmToList fm_1 <= fmToList fm_2)
828 -- ---------------------------------------------------------------------------
829 -- Efficiency pragmas for GHC
831 -- When the FiniteMap module is used in GHC, we specialise it for
832 -- \tr{Uniques}, for dastardly efficiency reasons.
834 #if defined(COMPILING_GHC) && __GLASGOW_HASKELL__ && !defined(REALLY_HASKELL_1_3)
836 {-# SPECIALIZE addListToFM
837 :: FiniteMap (FAST_STRING, FAST_STRING) elt -> [((FAST_STRING, FAST_STRING),elt)] -> FiniteMap (FAST_STRING, FAST_STRING) elt
838 , FiniteMap RdrName elt -> [(RdrName,elt)] -> FiniteMap RdrName elt
839 IF_NCG(COMMA FiniteMap Reg elt -> [(Reg COMMA elt)] -> FiniteMap Reg elt)
841 {-# SPECIALIZE addListToFM_C
842 :: (elt -> elt -> elt) -> FiniteMap TyCon elt -> [(TyCon,elt)] -> FiniteMap TyCon elt
843 , (elt -> elt -> elt) -> FiniteMap FAST_STRING elt -> [(FAST_STRING,elt)] -> FiniteMap FAST_STRING elt
844 IF_NCG(COMMA (elt -> elt -> elt) -> FiniteMap Reg elt -> [(Reg COMMA elt)] -> FiniteMap Reg elt)
846 {-# SPECIALIZE addToFM
847 :: FiniteMap CLabel elt -> CLabel -> elt -> FiniteMap CLabel elt
848 , FiniteMap FAST_STRING elt -> FAST_STRING -> elt -> FiniteMap FAST_STRING elt
849 , FiniteMap (FAST_STRING, FAST_STRING) elt -> (FAST_STRING, FAST_STRING) -> elt -> FiniteMap (FAST_STRING, FAST_STRING) elt
850 , FiniteMap RdrName elt -> RdrName -> elt -> FiniteMap RdrName elt
851 , FiniteMap OrigName elt -> OrigName -> elt -> FiniteMap OrigName elt
852 IF_NCG(COMMA FiniteMap Reg elt -> Reg -> elt -> FiniteMap Reg elt)
854 {-# SPECIALIZE addToFM_C
855 :: (elt -> elt -> elt) -> FiniteMap (RdrName, RdrName) elt -> (RdrName, RdrName) -> elt -> FiniteMap (RdrName, RdrName) elt
856 , (elt -> elt -> elt) -> FiniteMap (OrigName, OrigName) elt -> (OrigName, OrigName) -> elt -> FiniteMap (OrigName, OrigName) elt
857 , (elt -> elt -> elt) -> FiniteMap FAST_STRING elt -> FAST_STRING -> elt -> FiniteMap FAST_STRING elt
858 IF_NCG(COMMA (elt -> elt -> elt) -> FiniteMap Reg elt -> Reg -> elt -> FiniteMap Reg elt)
860 {-# SPECIALIZE bagToFM
861 :: Bag (FAST_STRING,elt) -> FiniteMap FAST_STRING elt
863 {-# SPECIALIZE delListFromFM
864 :: FiniteMap RdrName elt -> [RdrName] -> FiniteMap RdrName elt
865 , FiniteMap OrigName elt -> [OrigName] -> FiniteMap OrigName elt
866 , FiniteMap FAST_STRING elt -> [FAST_STRING] -> FiniteMap FAST_STRING elt
867 IF_NCG(COMMA FiniteMap Reg elt -> [Reg] -> FiniteMap Reg elt)
869 {-# SPECIALIZE listToFM
870 :: [([Char],elt)] -> FiniteMap [Char] elt
871 , [(FAST_STRING,elt)] -> FiniteMap FAST_STRING elt
872 , [((FAST_STRING,FAST_STRING),elt)] -> FiniteMap (FAST_STRING, FAST_STRING) elt
873 , [(OrigName,elt)] -> FiniteMap OrigName elt
874 IF_NCG(COMMA [(Reg COMMA elt)] -> FiniteMap Reg elt)
876 {-# SPECIALIZE lookupFM
877 :: FiniteMap CLabel elt -> CLabel -> Maybe elt
878 , FiniteMap [Char] elt -> [Char] -> Maybe elt
879 , FiniteMap FAST_STRING elt -> FAST_STRING -> Maybe elt
880 , FiniteMap (FAST_STRING,FAST_STRING) elt -> (FAST_STRING,FAST_STRING) -> Maybe elt
881 , FiniteMap OrigName elt -> OrigName -> Maybe elt
882 , FiniteMap (OrigName,OrigName) elt -> (OrigName,OrigName) -> Maybe elt
883 , FiniteMap RdrName elt -> RdrName -> Maybe elt
884 , FiniteMap (RdrName,RdrName) elt -> (RdrName,RdrName) -> Maybe elt
885 IF_NCG(COMMA FiniteMap Reg elt -> Reg -> Maybe elt)
887 {-# SPECIALIZE lookupWithDefaultFM
888 :: FiniteMap FAST_STRING elt -> elt -> FAST_STRING -> elt
889 IF_NCG(COMMA FiniteMap Reg elt -> elt -> Reg -> elt)
891 {-# SPECIALIZE plusFM
892 :: FiniteMap RdrName elt -> FiniteMap RdrName elt -> FiniteMap RdrName elt
893 , FiniteMap OrigName elt -> FiniteMap OrigName elt -> FiniteMap OrigName elt
894 , FiniteMap FAST_STRING elt -> FiniteMap FAST_STRING elt -> FiniteMap FAST_STRING elt
895 IF_NCG(COMMA FiniteMap Reg elt -> FiniteMap Reg elt -> FiniteMap Reg elt)
897 {-# SPECIALIZE plusFM_C
898 :: (elt -> elt -> elt) -> FiniteMap FAST_STRING elt -> FiniteMap FAST_STRING elt -> FiniteMap FAST_STRING elt
899 IF_NCG(COMMA (elt -> elt -> elt) -> FiniteMap Reg elt -> FiniteMap Reg elt -> FiniteMap Reg elt)
902 #endif /* compiling for GHC */