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 -- A finite map implementation, derived from the paper:
12 -- /Efficient sets: a balancing act/, S. Adams,
13 -- Journal of functional programming 3(4) Oct 1993, pp553-562
15 -----------------------------------------------------------------------------
17 -- ToDo: clean up, remove the COMPILING_GHC stuff.
19 -- The code is SPECIALIZEd to various highly-desirable types (e.g., Id)
20 -- near the end (only \tr{#ifdef COMPILING_GHC}).
23 #include "HsVersions.h"
24 #define IF_NOT_GHC(a) {--}
26 #define ASSERT(e) {--}
27 #define IF_NOT_GHC(a) a
29 #define _tagCmp compare
35 #if defined(COMPILING_GHC) && defined(DEBUG_FINITEMAPS)/* NB NB NB */
36 #define OUTPUTABLE_key , Outputable key
38 #define OUTPUTABLE_key {--}
41 module Data.FiniteMap (
42 -- * The @FiniteMap@ type
43 FiniteMap, -- abstract type
46 emptyFM, unitFM, listToFM,
48 -- * Lookup operations
49 lookupFM, lookupWithDefaultFM,
58 -- * Deleting elements
59 IF_NOT_GHC(delFromFM COMMA)
66 -- * Extracting information
67 fmToList, keysFM, eltsFM,
73 IF_NOT_GHC(intersectFM COMMA)
74 IF_NOT_GHC(intersectFM_C COMMA)
75 IF_NOT_GHC(mapFM COMMA filterFM COMMA)
77 foldFM_GE, fmToList_GE, keysFM_GE, eltsFM_GE,
78 foldFM_LE, fmToList_LE, keysFM_LE, eltsFM_LE,
87 import Data.Maybe ( isJust )
88 #ifdef __GLASGOW_HASKELL__
101 import Bag ( foldBag )
103 # if ! OMIT_NATIVE_CODEGEN
106 # define IF_NCG(a) {--}
110 -- SIGH: but we use unboxed "sizes"...
111 #if __GLASGOW_HASKELL__
112 #define IF_GHC(a,b) a
114 #define IF_GHC(a,b) b
118 -- ---------------------------------------------------------------------------
119 -- The signature of the module
121 -- | An empty 'FiniteMap'.
122 emptyFM :: FiniteMap key elt
124 -- | A 'FiniteMap' containing a single mapping
125 unitFM :: key -> elt -> FiniteMap key elt
127 -- | Makes a 'FiniteMap' from a list of @(key,value)@ pairs. In the
128 -- case of duplicates, the last is taken
129 listToFM :: (Ord key OUTPUTABLE_key) => [(key,elt)] -> FiniteMap key elt
132 bagToFM :: (Ord key OUTPUTABLE_key) => Bag (key,elt) -> FiniteMap key elt
133 -- In the case of duplicates, who knows which is taken
136 -- ADDING AND DELETING
138 -- | Adds an element to a 'FiniteMap'. Any previous mapping with the same
139 -- key is overwritten.
140 addToFM :: (Ord key OUTPUTABLE_key) => FiniteMap key elt -> key -> elt -> FiniteMap key elt
142 -- | Adds a list of elements to a 'FiniteMap', in the order given in
143 -- the list. Overwrites previous mappings.
144 addListToFM :: (Ord key OUTPUTABLE_key) => FiniteMap key elt -> [(key,elt)] -> FiniteMap key elt
146 -- Combines with previous binding
147 -- In the combining function, the first argument is the "old" element,
148 -- while the second is the "new" one.
150 -- | Adds an element to a 'FiniteMap'. If there is already an element
151 -- with the same key, then the specified combination function is used
152 -- to calculate the new value. The already present element is passed as
153 -- the first argument and the new element to add as second.
154 addToFM_C :: (Ord key OUTPUTABLE_key) => (elt -> elt -> elt)
155 -> FiniteMap key elt -> key -> elt
158 -- | A list version of 'addToFM_C'. The elements are added in the
159 -- order given in the list.
160 addListToFM_C :: (Ord key OUTPUTABLE_key) => (elt -> elt -> elt)
161 -> FiniteMap key elt -> [(key,elt)]
164 -- | Deletes an element from a 'FiniteMap'. If there is no element with
165 -- the specified key, then the original 'FiniteMap' is returned.
166 delFromFM :: (Ord key OUTPUTABLE_key) => FiniteMap key elt -> key -> FiniteMap key elt
168 -- | List version of 'delFromFM'.
169 delListFromFM :: (Ord key OUTPUTABLE_key) => FiniteMap key elt -> [key] -> FiniteMap key elt
171 -- | Combine two 'FiniteMap's. Mappings in the second argument shadow
172 -- those in the first.
173 plusFM :: (Ord key OUTPUTABLE_key) => FiniteMap key elt -> FiniteMap key elt
176 -- | Combine two 'FiniteMap's. The specified combination function is
177 -- used to calculate the new value when there are two elements with
179 plusFM_C :: (Ord key OUTPUTABLE_key) => (elt -> elt -> elt)
180 -> FiniteMap key elt -> FiniteMap key elt -> FiniteMap key elt
182 -- | @(minusFM a1 a2)@ deletes from @a1@ any mappings which are bound in @a2@
183 minusFM :: (Ord key OUTPUTABLE_key) => FiniteMap key elt -> FiniteMap key elt -> FiniteMap key elt
185 -- | @(intersectFM a1 a2)@ returns a new 'FiniteMap' containing
186 -- mappings from @a1@ for which @a2@ also has a mapping with the same
188 intersectFM :: (Ord key OUTPUTABLE_key) => FiniteMap key elt -> FiniteMap key elt -> FiniteMap key elt
190 -- | Returns the interesction of two mappings, using the specified
191 -- combination function to combine values.
192 intersectFM_C :: (Ord key OUTPUTABLE_key) => (elt1 -> elt2 -> elt3)
193 -> FiniteMap key elt1 -> FiniteMap key elt2 -> FiniteMap key elt3
195 -- MAPPING, FOLDING, FILTERING
196 foldFM :: (key -> elt -> a -> a) -> a -> FiniteMap key elt -> a
197 mapFM :: (key -> elt1 -> elt2) -> FiniteMap key elt1 -> FiniteMap key elt2
198 filterFM :: (Ord key OUTPUTABLE_key) => (key -> elt -> Bool)
199 -> FiniteMap key elt -> FiniteMap key elt
202 sizeFM :: FiniteMap key elt -> Int
203 isEmptyFM :: FiniteMap key elt -> Bool
205 -- | Returns 'True' if the specified @key@ has a mapping in this
206 -- 'FiniteMap', or 'False' otherwise.
207 elemFM :: (Ord key OUTPUTABLE_key) => key -> FiniteMap key elt -> Bool
209 -- | Looks up a key in a 'FiniteMap', returning @'Just' v@ if the key
210 -- was found with value @v@, or 'Nothing' otherwise.
211 lookupFM :: (Ord key OUTPUTABLE_key) => FiniteMap key elt -> key -> Maybe elt
213 -- | Looks up a key in a 'FiniteMap', returning @elt@ if the specified
214 -- @key@ was not found.
216 :: (Ord key OUTPUTABLE_key) => FiniteMap key elt -> elt -> key -> elt
217 -- lookupWithDefaultFM supplies a "default" elt
218 -- to return for an unmapped key
222 -- | Convert a 'FiniteMap' to a @[(key, elt)]@ sorted by 'Ord' key
224 fmToList :: FiniteMap key elt -> [(key,elt)]
226 -- | Extract the keys from a 'FiniteMap', in the order of the keys, so
228 -- > keysFM == map fst . fmToList
230 keysFM :: FiniteMap key elt -> [key]
232 -- | Extract the elements from a 'FiniteMap', in the order of the keys, so
234 -- > eltsFM == map snd . fmToList
236 eltsFM :: FiniteMap key elt -> [elt]
238 -- ---------------------------------------------------------------------------
239 -- The @FiniteMap@ data type, and building of same
241 -- Invariants about @FiniteMap@:
243 -- * all keys in a FiniteMap are distinct
245 -- * all keys in left subtree are $<$ key in Branch and
246 -- all keys in right subtree are $>$ key in Branch
248 -- * size field of a Branch gives number of Branch nodes in the tree
250 -- * size of left subtree is differs from size of right subtree by a
251 -- factor of at most \tr{sIZE_RATIO}
253 -- | A mapping from @key@s to @elt@s.
254 data FiniteMap key elt
256 | Branch key elt -- Key and elt stored here
257 IF_GHC(Int#,Int{-STRICT-}) -- Size >= 1
258 (FiniteMap key elt) -- Children
265 = Branch bottom bottom IF_GHC(0#,0) bottom bottom
267 bottom = panic "emptyFM"
270 -- #define EmptyFM (Branch _ _ IF_GHC(0#,0) _ _)
272 unitFM key elt = Branch key elt IF_GHC(1#,1) emptyFM emptyFM
274 listToFM = addListToFM emptyFM
277 bagToFM = foldBag plusFM (\ (k,v) -> unitFM k v) emptyFM
280 instance (Show k, Show e) => Show (FiniteMap k e) where
281 showsPrec p m = showsPrec p (fmToList m)
283 -- ---------------------------------------------------------------------------
284 -- Adding to and deleting from @FiniteMaps@
286 addToFM fm key elt = addToFM_C (\ old new -> new) fm key elt
288 addToFM_C combiner EmptyFM key elt = unitFM key elt
289 addToFM_C combiner (Branch key elt size fm_l fm_r) new_key new_elt
290 #ifdef __GLASGOW_HASKELL__
291 = case _tagCmp new_key key of
292 _LT -> mkBalBranch key elt (addToFM_C combiner fm_l new_key new_elt) fm_r
293 _GT -> mkBalBranch key elt fm_l (addToFM_C combiner fm_r new_key new_elt)
294 _EQ -> Branch new_key (combiner elt new_elt) size fm_l fm_r
296 | new_key < key = mkBalBranch key elt (addToFM_C combiner fm_l new_key new_elt) fm_r
297 | new_key > key = mkBalBranch key elt fm_l (addToFM_C combiner fm_r new_key new_elt)
298 | otherwise = Branch new_key (combiner elt new_elt) size fm_l fm_r
301 addListToFM fm key_elt_pairs = addListToFM_C (\ old new -> new) fm key_elt_pairs
303 addListToFM_C combiner fm key_elt_pairs
304 = foldl add fm key_elt_pairs -- foldl adds from the left
306 add fmap (key,elt) = addToFM_C combiner fmap key elt
309 delFromFM EmptyFM del_key = emptyFM
310 delFromFM (Branch key elt size fm_l fm_r) del_key
311 #if __GLASGOW_HASKELL__
312 = case _tagCmp del_key key of
313 _GT -> mkBalBranch key elt fm_l (delFromFM fm_r del_key)
314 _LT -> mkBalBranch key elt (delFromFM fm_l del_key) fm_r
315 _EQ -> glueBal fm_l fm_r
318 = mkBalBranch key elt fm_l (delFromFM fm_r del_key)
321 = mkBalBranch key elt (delFromFM fm_l del_key) fm_r
327 delListFromFM fm keys = foldl delFromFM fm keys
329 -- ---------------------------------------------------------------------------
330 -- Combining @FiniteMaps@
332 plusFM_C combiner EmptyFM fm2 = fm2
333 plusFM_C combiner fm1 EmptyFM = fm1
334 plusFM_C combiner fm1 (Branch split_key elt2 _ left right)
335 = mkVBalBranch split_key new_elt
336 (plusFM_C combiner lts left)
337 (plusFM_C combiner gts right)
339 lts = splitLT fm1 split_key
340 gts = splitGT fm1 split_key
341 new_elt = case lookupFM fm1 split_key of
343 Just elt1 -> combiner elt1 elt2
345 -- It's worth doing plusFM specially, because we don't need
346 -- to do the lookup in fm1.
348 plusFM EmptyFM fm2 = fm2
349 plusFM fm1 EmptyFM = fm1
350 plusFM fm1 (Branch split_key elt1 _ left right)
351 = mkVBalBranch split_key elt1 (plusFM lts left) (plusFM gts right)
353 lts = splitLT fm1 split_key
354 gts = splitGT fm1 split_key
356 minusFM EmptyFM fm2 = emptyFM
357 minusFM fm1 EmptyFM = fm1
358 minusFM fm1 (Branch split_key elt _ left right)
359 = glueVBal (minusFM lts left) (minusFM gts right)
360 -- The two can be way different, so we need glueVBal
362 lts = splitLT fm1 split_key -- NB gt and lt, so the equal ones
363 gts = splitGT fm1 split_key -- are not in either.
365 intersectFM fm1 fm2 = intersectFM_C (\ left right -> right) fm1 fm2
367 intersectFM_C combiner fm1 EmptyFM = emptyFM
368 intersectFM_C combiner EmptyFM fm2 = emptyFM
369 intersectFM_C combiner fm1 (Branch split_key elt2 _ left right)
371 | isJust maybe_elt1 -- split_elt *is* in intersection
372 = mkVBalBranch split_key (combiner elt1 elt2) (intersectFM_C combiner lts left)
373 (intersectFM_C combiner gts right)
375 | otherwise -- split_elt is *not* in intersection
376 = glueVBal (intersectFM_C combiner lts left) (intersectFM_C combiner gts right)
379 lts = splitLT fm1 split_key -- NB gt and lt, so the equal ones
380 gts = splitGT fm1 split_key -- are not in either.
382 maybe_elt1 = lookupFM fm1 split_key
383 Just elt1 = maybe_elt1
386 -- ---------------------------------------------------------------------------
387 -- Mapping, folding, and filtering with @FiniteMaps@
389 foldFM k z EmptyFM = z
390 foldFM k z (Branch key elt _ fm_l fm_r)
391 = foldFM k (k key elt (foldFM k z fm_r)) fm_l
393 mapFM f EmptyFM = emptyFM
394 mapFM f (Branch key elt size fm_l fm_r)
395 = Branch key (f key elt) size (mapFM f fm_l) (mapFM f fm_r)
397 filterFM p EmptyFM = emptyFM
398 filterFM p (Branch key elt _ fm_l fm_r)
399 | p key elt -- Keep the item
400 = mkVBalBranch key elt (filterFM p fm_l) (filterFM p fm_r)
402 | otherwise -- Drop the item
403 = glueVBal (filterFM p fm_l) (filterFM p fm_r)
406 -- ---------------------------------------------------------------------------
407 -- Interrogating @FiniteMaps@
409 --{-# INLINE sizeFM #-}
411 sizeFM (Branch _ _ size _ _) = IF_GHC(I# size, size)
413 isEmptyFM fm = sizeFM fm == 0
415 lookupFM EmptyFM key = Nothing
416 lookupFM (Branch key elt _ fm_l fm_r) key_to_find
417 #if __GLASGOW_HASKELL__
418 = case _tagCmp key_to_find key of
419 _LT -> lookupFM fm_l key_to_find
420 _GT -> lookupFM fm_r key_to_find
423 | key_to_find < key = lookupFM fm_l key_to_find
424 | key_to_find > key = lookupFM fm_r key_to_find
425 | otherwise = Just elt
429 = case (lookupFM fm key) of { Nothing -> False; Just elt -> True }
431 lookupWithDefaultFM fm deflt key
432 = case (lookupFM fm key) of { Nothing -> deflt; Just elt -> elt }
435 -- ---------------------------------------------------------------------------
436 -- Listifying @FiniteMaps@
438 fmToList fm = foldFM (\ key elt rest -> (key,elt) : rest) [] fm
439 keysFM fm = foldFM (\ key elt rest -> key : rest) [] fm
440 eltsFM fm = foldFM (\ key elt rest -> elt : rest) [] fm
443 -- ---------------------------------------------------------------------------
444 -- Bulk operations on all keys >= or <= a certain threshold
446 -- | Fold through all elements greater than or equal to the supplied key,
447 -- in increasing order.
448 foldFM_GE :: Ord key => (key -> elt -> a -> a) -> a -> key ->
449 FiniteMap key elt -> a
451 foldFM_GE k z fr EmptyFM = z
452 foldFM_GE k z fr (Branch key elt _ fm_l fm_r)
453 | key >= fr = foldFM_GE k (k key elt (foldFM_GE k z fr fm_r)) fr fm_l
454 | otherwise = foldFM_GE k z fr fm_r
456 -- | List elements greater than or equal to the supplied key, in increasing
458 fmToList_GE :: Ord key => FiniteMap key elt -> key -> [(key,elt)]
459 fmToList_GE fm fr = foldFM_GE (\ key elt rest -> (key,elt) : rest) [] fr fm
461 -- | List keys greater than or equal to the supplied key, in increasing order
462 keysFM_GE :: Ord key => FiniteMap key elt -> key -> [key]
463 keysFM_GE fm fr = foldFM_GE (\ key elt rest -> key : rest) [] fr fm
465 -- | List elements corresponding to keys greater than or equal to the supplied
466 -- key, in increasing order of key.
467 eltsFM_GE :: Ord key => FiniteMap key elt -> key -> [elt]
468 eltsFM_GE fm fr = foldFM_GE (\ key elt rest -> elt : rest) [] fr fm
470 -- | Fold through all elements less than or equal to the supplied key,
471 -- in decreasing order.
472 foldFM_LE :: Ord key => (key -> elt -> a -> a) -> a -> key ->
473 FiniteMap key elt -> a
474 foldFM_LE k z fr EmptyFM = z
475 foldFM_LE k z fr (Branch key elt _ fm_l fm_r)
476 | key <= fr = foldFM_LE k (k key elt (foldFM_LE k z fr fm_l)) fr fm_r
477 | otherwise = foldFM_LE k z fr fm_l
479 -- | List elements greater than or equal to the supplied key, in decreasing
481 fmToList_LE :: Ord key => FiniteMap key elt -> key -> [(key,elt)]
482 fmToList_LE fm fr = foldFM_LE (\ key elt rest -> (key,elt) : rest) [] fr fm
484 -- | List keys greater than or equal to the supplied key, in decreasing order
485 keysFM_LE :: Ord key => FiniteMap key elt -> key -> [key]
486 keysFM_LE fm fr = foldFM_LE (\ key elt rest -> key : rest) [] fr fm
488 -- | List elements corresponding to keys greater than or equal to the supplied
489 -- key, in decreasing order of key.
490 eltsFM_LE :: Ord key => FiniteMap key elt -> key -> [elt]
491 eltsFM_LE fm fr = foldFM_LE (\ key elt rest -> elt : rest) [] fr fm
493 -- ---------------------------------------------------------------------------
494 -- Getting minimum and maximum key out.
495 -- ---------------------------------------------------------------------------
497 -- | Extract minimum key, or Nothing if the map is empty.
498 minFM :: Ord key => FiniteMap key elt -> Maybe key
499 minFM EmptyFM = Nothing
500 minFM (Branch key _ _ fm_l _) =
503 Just key1 -> Just key1
505 -- | Extract maximum key, or Nothing if the map is empty.
506 maxFM :: Ord key => FiniteMap key elt -> Maybe key
507 maxFM EmptyFM = Nothing
508 maxFM (Branch key _ _ _ fm_r) =
511 Just key1 -> Just key1
514 -- ---------------------------------------------------------------------------
515 -- The implementation of balancing
517 -- Basic construction of a @FiniteMap@:
519 -- @mkBranch@ simply gets the size component right. This is the ONLY
520 -- (non-trivial) place the Branch object is built, so the ASSERTion
521 -- recursively checks consistency. (The trivial use of Branch is in
527 mkBranch :: (Ord key OUTPUTABLE_key) -- Used for the assertion checking only
530 -> FiniteMap key elt -> FiniteMap key elt
533 mkBranch which key elt fm_l fm_r
534 = --ASSERT( left_ok && right_ok && balance_ok )
535 #if defined(COMPILING_GHC) && defined(DEBUG_FINITEMAPS)
536 if not ( left_ok && right_ok && balance_ok ) then
537 pprPanic ("mkBranch:"++show which) (ppAboves [ppr PprDebug [left_ok, right_ok, balance_ok],
544 result = Branch key elt (unbox (1 + left_size + right_size)) fm_l fm_r
546 -- if sizeFM result <= 8 then
549 -- pprTrace ("mkBranch:"++(show which)) (ppr PprDebug result) (
553 left_ok = case fm_l of
555 Branch left_key _ _ _ _ -> let
556 biggest_left_key = fst (findMax fm_l)
558 biggest_left_key < key
559 right_ok = case fm_r of
561 Branch right_key _ _ _ _ -> let
562 smallest_right_key = fst (findMin fm_r)
564 key < smallest_right_key
565 balance_ok = True -- sigh
568 = -- Both subtrees have one or no elements...
569 (left_size + right_size <= 1)
570 -- NO || left_size == 0 -- ???
571 -- NO || right_size == 0 -- ???
572 -- ... or the number of elements in a subtree does not exceed
573 -- sIZE_RATIO times the number of elements in the other subtree
574 || (left_size * sIZE_RATIO >= right_size &&
575 right_size * sIZE_RATIO >= left_size)
578 left_size = sizeFM fm_l
579 right_size = sizeFM fm_r
581 #if __GLASGOW_HASKELL__
583 unbox (I# size) = size
590 -- ---------------------------------------------------------------------------
591 -- {\em Balanced} construction of a @FiniteMap@
593 -- @mkBalBranch@ rebalances, assuming that the subtrees aren't too far
596 mkBalBranch :: (Ord key OUTPUTABLE_key)
598 -> FiniteMap key elt -> FiniteMap key elt
601 mkBalBranch key elt fm_L fm_R
603 | size_l + size_r < 2
604 = mkBranch 1{-which-} key elt fm_L fm_R
606 | size_r > sIZE_RATIO * size_l -- Right tree too big
608 Branch _ _ _ fm_rl fm_rr
609 | sizeFM fm_rl < 2 * sizeFM fm_rr -> single_L fm_L fm_R
610 | otherwise -> double_L fm_L fm_R
611 -- Other case impossible
613 | size_l > sIZE_RATIO * size_r -- Left tree too big
615 Branch _ _ _ fm_ll fm_lr
616 | sizeFM fm_lr < 2 * sizeFM fm_ll -> single_R fm_L fm_R
617 | otherwise -> double_R fm_L fm_R
618 -- Other case impossible
620 | otherwise -- No imbalance
621 = mkBranch 2{-which-} key elt fm_L fm_R
627 single_L fm_l (Branch key_r elt_r _ fm_rl fm_rr)
628 = mkBranch 3{-which-} key_r elt_r (mkBranch 4{-which-} key elt fm_l fm_rl) fm_rr
630 double_L fm_l (Branch key_r elt_r _ (Branch key_rl elt_rl _ fm_rll fm_rlr) fm_rr)
631 = mkBranch 5{-which-} key_rl elt_rl (mkBranch 6{-which-} key elt fm_l fm_rll)
632 (mkBranch 7{-which-} key_r elt_r fm_rlr fm_rr)
634 single_R (Branch key_l elt_l _ fm_ll fm_lr) fm_r
635 = mkBranch 8{-which-} key_l elt_l fm_ll (mkBranch 9{-which-} key elt fm_lr fm_r)
637 double_R (Branch key_l elt_l _ fm_ll (Branch key_lr elt_lr _ fm_lrl fm_lrr)) fm_r
638 = mkBranch 10{-which-} key_lr elt_lr (mkBranch 11{-which-} key_l elt_l fm_ll fm_lrl)
639 (mkBranch 12{-which-} key elt fm_lrr fm_r)
642 mkVBalBranch :: (Ord key OUTPUTABLE_key)
644 -> FiniteMap key elt -> FiniteMap key elt
647 -- Assert: in any call to (mkVBalBranch_C comb key elt l r),
648 -- (a) all keys in l are < all keys in r
649 -- (b) all keys in l are < key
650 -- (c) all keys in r are > key
652 mkVBalBranch key elt EmptyFM fm_r = addToFM fm_r key elt
653 mkVBalBranch key elt fm_l EmptyFM = addToFM fm_l key elt
655 mkVBalBranch key elt fm_l@(Branch key_l elt_l _ fm_ll fm_lr)
656 fm_r@(Branch key_r elt_r _ fm_rl fm_rr)
657 | sIZE_RATIO * size_l < size_r
658 = mkBalBranch key_r elt_r (mkVBalBranch key elt fm_l fm_rl) fm_rr
660 | sIZE_RATIO * size_r < size_l
661 = mkBalBranch key_l elt_l fm_ll (mkVBalBranch key elt fm_lr fm_r)
664 = mkBranch 13{-which-} key elt fm_l fm_r
670 -- ---------------------------------------------------------------------------
671 -- Gluing two trees together
673 -- @glueBal@ assumes its two arguments aren't too far out of whack, just
674 -- like @mkBalBranch@. But: all keys in first arg are $<$ all keys in
677 glueBal :: (Ord key OUTPUTABLE_key)
678 => FiniteMap key elt -> FiniteMap key elt
681 glueBal EmptyFM fm2 = fm2
682 glueBal fm1 EmptyFM = fm1
684 -- The case analysis here (absent in Adams' program) is really to deal
685 -- with the case where fm2 is a singleton. Then deleting the minimum means
686 -- we pass an empty tree to mkBalBranch, which breaks its invariant.
687 | sizeFM fm2 > sizeFM fm1
688 = mkBalBranch mid_key2 mid_elt2 fm1 (deleteMin fm2)
691 = mkBalBranch mid_key1 mid_elt1 (deleteMax fm1) fm2
693 (mid_key1, mid_elt1) = findMax fm1
694 (mid_key2, mid_elt2) = findMin fm2
696 -- @glueVBal@ copes with arguments which can be of any size.
697 -- But: all keys in first arg are $<$ all keys in second.
699 glueVBal :: (Ord key OUTPUTABLE_key)
700 => FiniteMap key elt -> FiniteMap key elt
703 glueVBal EmptyFM fm2 = fm2
704 glueVBal fm1 EmptyFM = fm1
705 glueVBal fm_l@(Branch key_l elt_l _ fm_ll fm_lr)
706 fm_r@(Branch key_r elt_r _ fm_rl fm_rr)
707 | sIZE_RATIO * size_l < size_r
708 = mkBalBranch key_r elt_r (glueVBal fm_l fm_rl) fm_rr
710 | sIZE_RATIO * size_r < size_l
711 = mkBalBranch key_l elt_l fm_ll (glueVBal fm_lr fm_r)
713 | otherwise -- We now need the same two cases as in glueBal above.
720 -- ---------------------------------------------------------------------------
723 splitLT, splitGT :: (Ord key OUTPUTABLE_key) => FiniteMap key elt -> key -> FiniteMap key elt
725 -- splitLT fm split_key = fm restricted to keys < split_key
726 -- splitGT fm split_key = fm restricted to keys > split_key
728 splitLT EmptyFM split_key = emptyFM
729 splitLT (Branch key elt _ fm_l fm_r) split_key
730 #if __GLASGOW_HASKELL__
731 = case _tagCmp split_key key of
732 _LT -> splitLT fm_l split_key
733 _GT -> mkVBalBranch key elt fm_l (splitLT fm_r split_key)
736 | split_key < key = splitLT fm_l split_key
737 | split_key > key = mkVBalBranch key elt fm_l (splitLT fm_r split_key)
741 splitGT EmptyFM split_key = emptyFM
742 splitGT (Branch key elt _ fm_l fm_r) split_key
743 #if __GLASGOW_HASKELL__
744 = case _tagCmp split_key key of
745 _GT -> splitGT fm_r split_key
746 _LT -> mkVBalBranch key elt (splitGT fm_l split_key) fm_r
749 | split_key > key = splitGT fm_r split_key
750 | split_key < key = mkVBalBranch key elt (splitGT fm_l split_key) fm_r
754 findMin :: FiniteMap key elt -> (key,elt)
755 findMin (Branch key elt _ EmptyFM _) = (key,elt)
756 findMin (Branch key elt _ fm_l _) = findMin fm_l
758 deleteMin :: (Ord key OUTPUTABLE_key) => FiniteMap key elt -> FiniteMap key elt
759 deleteMin (Branch key elt _ EmptyFM fm_r) = fm_r
760 deleteMin (Branch key elt _ fm_l fm_r) = mkBalBranch key elt (deleteMin fm_l) fm_r
762 findMax :: FiniteMap key elt -> (key,elt)
763 findMax (Branch key elt _ _ EmptyFM) = (key,elt)
764 findMax (Branch key elt _ _ fm_r) = findMax fm_r
766 deleteMax :: (Ord key OUTPUTABLE_key) => FiniteMap key elt -> FiniteMap key elt
767 deleteMax (Branch key elt _ fm_l EmptyFM) = fm_l
768 deleteMax (Branch key elt _ fm_l fm_r) = mkBalBranch key elt fm_l (deleteMax fm_r)
771 -- ---------------------------------------------------------------------------
774 #if defined(COMPILING_GHC) && defined(DEBUG_FINITEMAPS)
776 instance (Outputable key) => Outputable (FiniteMap key elt) where
777 ppr sty fm = pprX sty fm
779 pprX sty EmptyFM = ppChar '!'
780 pprX sty (Branch key elt sz fm_l fm_r)
781 = ppBesides [ppLparen, pprX sty fm_l, ppSP,
782 ppr sty key, ppSP, ppInt (IF_GHC(I# sz, sz)), ppSP,
783 pprX sty fm_r, ppRparen]
786 #ifndef COMPILING_GHC
787 instance (Eq key, Eq elt) => Eq (FiniteMap key elt) where
788 fm_1 == fm_2 = (sizeFM fm_1 == sizeFM fm_2) && -- quick test
789 (fmToList fm_1 == fmToList fm_2)
791 {- NO: not clear what The Right Thing to do is:
792 instance (Ord key, Ord elt) => Ord (FiniteMap key elt) where
793 fm_1 <= fm_2 = (sizeFM fm_1 <= sizeFM fm_2) && -- quick test
794 (fmToList fm_1 <= fmToList fm_2)
798 -- ---------------------------------------------------------------------------
799 -- Efficiency pragmas for GHC
801 -- When the FiniteMap module is used in GHC, we specialise it for
802 -- \tr{Uniques}, for dastardly efficiency reasons.
804 #if defined(COMPILING_GHC) && __GLASGOW_HASKELL__ && !defined(REALLY_HASKELL_1_3)
806 {-# SPECIALIZE addListToFM
807 :: FiniteMap (FAST_STRING, FAST_STRING) elt -> [((FAST_STRING, FAST_STRING),elt)] -> FiniteMap (FAST_STRING, FAST_STRING) elt
808 , FiniteMap RdrName elt -> [(RdrName,elt)] -> FiniteMap RdrName elt
809 IF_NCG(COMMA FiniteMap Reg elt -> [(Reg COMMA elt)] -> FiniteMap Reg elt)
811 {-# SPECIALIZE addListToFM_C
812 :: (elt -> elt -> elt) -> FiniteMap TyCon elt -> [(TyCon,elt)] -> FiniteMap TyCon elt
813 , (elt -> elt -> elt) -> FiniteMap FAST_STRING elt -> [(FAST_STRING,elt)] -> FiniteMap FAST_STRING elt
814 IF_NCG(COMMA (elt -> elt -> elt) -> FiniteMap Reg elt -> [(Reg COMMA elt)] -> FiniteMap Reg elt)
816 {-# SPECIALIZE addToFM
817 :: FiniteMap CLabel elt -> CLabel -> elt -> FiniteMap CLabel elt
818 , FiniteMap FAST_STRING elt -> FAST_STRING -> elt -> FiniteMap FAST_STRING elt
819 , FiniteMap (FAST_STRING, FAST_STRING) elt -> (FAST_STRING, FAST_STRING) -> elt -> FiniteMap (FAST_STRING, FAST_STRING) elt
820 , FiniteMap RdrName elt -> RdrName -> elt -> FiniteMap RdrName elt
821 , FiniteMap OrigName elt -> OrigName -> elt -> FiniteMap OrigName elt
822 IF_NCG(COMMA FiniteMap Reg elt -> Reg -> elt -> FiniteMap Reg elt)
824 {-# SPECIALIZE addToFM_C
825 :: (elt -> elt -> elt) -> FiniteMap (RdrName, RdrName) elt -> (RdrName, RdrName) -> elt -> FiniteMap (RdrName, RdrName) elt
826 , (elt -> elt -> elt) -> FiniteMap (OrigName, OrigName) elt -> (OrigName, OrigName) -> elt -> FiniteMap (OrigName, OrigName) elt
827 , (elt -> elt -> elt) -> FiniteMap FAST_STRING elt -> FAST_STRING -> elt -> FiniteMap FAST_STRING elt
828 IF_NCG(COMMA (elt -> elt -> elt) -> FiniteMap Reg elt -> Reg -> elt -> FiniteMap Reg elt)
830 {-# SPECIALIZE bagToFM
831 :: Bag (FAST_STRING,elt) -> FiniteMap FAST_STRING elt
833 {-# SPECIALIZE delListFromFM
834 :: FiniteMap RdrName elt -> [RdrName] -> FiniteMap RdrName elt
835 , FiniteMap OrigName elt -> [OrigName] -> FiniteMap OrigName elt
836 , FiniteMap FAST_STRING elt -> [FAST_STRING] -> FiniteMap FAST_STRING elt
837 IF_NCG(COMMA FiniteMap Reg elt -> [Reg] -> FiniteMap Reg elt)
839 {-# SPECIALIZE listToFM
840 :: [([Char],elt)] -> FiniteMap [Char] elt
841 , [(FAST_STRING,elt)] -> FiniteMap FAST_STRING elt
842 , [((FAST_STRING,FAST_STRING),elt)] -> FiniteMap (FAST_STRING, FAST_STRING) elt
843 , [(OrigName,elt)] -> FiniteMap OrigName elt
844 IF_NCG(COMMA [(Reg COMMA elt)] -> FiniteMap Reg elt)
846 {-# SPECIALIZE lookupFM
847 :: FiniteMap CLabel elt -> CLabel -> Maybe elt
848 , FiniteMap [Char] elt -> [Char] -> Maybe elt
849 , FiniteMap FAST_STRING elt -> FAST_STRING -> Maybe elt
850 , FiniteMap (FAST_STRING,FAST_STRING) elt -> (FAST_STRING,FAST_STRING) -> Maybe elt
851 , FiniteMap OrigName elt -> OrigName -> Maybe elt
852 , FiniteMap (OrigName,OrigName) elt -> (OrigName,OrigName) -> Maybe elt
853 , FiniteMap RdrName elt -> RdrName -> Maybe elt
854 , FiniteMap (RdrName,RdrName) elt -> (RdrName,RdrName) -> Maybe elt
855 IF_NCG(COMMA FiniteMap Reg elt -> Reg -> Maybe elt)
857 {-# SPECIALIZE lookupWithDefaultFM
858 :: FiniteMap FAST_STRING elt -> elt -> FAST_STRING -> elt
859 IF_NCG(COMMA FiniteMap Reg elt -> elt -> Reg -> elt)
861 {-# SPECIALIZE plusFM
862 :: FiniteMap RdrName elt -> FiniteMap RdrName elt -> FiniteMap RdrName elt
863 , FiniteMap OrigName elt -> FiniteMap OrigName elt -> FiniteMap OrigName elt
864 , FiniteMap FAST_STRING elt -> FiniteMap FAST_STRING elt -> FiniteMap FAST_STRING elt
865 IF_NCG(COMMA FiniteMap Reg elt -> FiniteMap Reg elt -> FiniteMap Reg elt)
867 {-# SPECIALIZE plusFM_C
868 :: (elt -> elt -> elt) -> FiniteMap FAST_STRING elt -> FiniteMap FAST_STRING elt -> FiniteMap FAST_STRING elt
869 IF_NCG(COMMA (elt -> elt -> elt) -> FiniteMap Reg elt -> FiniteMap Reg elt -> FiniteMap Reg elt)
872 #endif /* compiling for GHC */