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 Prelude -- necessary to get dependencies right
89 import Data.Maybe ( isJust )
90 #ifdef __GLASGOW_HASKELL__
103 import Bag ( foldBag )
105 # if ! OMIT_NATIVE_CODEGEN
108 # define IF_NCG(a) {--}
112 -- SIGH: but we use unboxed "sizes"...
113 #if __GLASGOW_HASKELL__
114 #define IF_GHC(a,b) a
116 #define IF_GHC(a,b) b
120 -- ---------------------------------------------------------------------------
121 -- The signature of the module
123 -- | An empty 'FiniteMap'.
124 emptyFM :: FiniteMap key elt
126 -- | A 'FiniteMap' containing a single mapping
127 unitFM :: key -> elt -> FiniteMap key elt
129 -- | Makes a 'FiniteMap' from a list of @(key,value)@ pairs. In the
130 -- case of duplicates, the last is taken
131 listToFM :: (Ord key OUTPUTABLE_key) => [(key,elt)] -> FiniteMap key elt
134 bagToFM :: (Ord key OUTPUTABLE_key) => Bag (key,elt) -> FiniteMap key elt
135 -- In the case of duplicates, who knows which is taken
138 -- ADDING AND DELETING
140 -- | Adds an element to a 'FiniteMap'. Any previous mapping with the same
141 -- key is overwritten.
142 addToFM :: (Ord key OUTPUTABLE_key) => FiniteMap key elt -> key -> elt -> FiniteMap key elt
144 -- | Adds a list of elements to a 'FiniteMap', in the order given in
145 -- the list. Overwrites previous mappings.
146 addListToFM :: (Ord key OUTPUTABLE_key) => FiniteMap key elt -> [(key,elt)] -> FiniteMap key elt
148 -- Combines with previous binding
149 -- In the combining function, the first argument is the "old" element,
150 -- while the second is the "new" one.
152 -- | Adds an element to a 'FiniteMap'. If there is already an element
153 -- with the same key, then the specified combination function is used
154 -- to calculate the new value. The already present element is passed as
155 -- the first argument and the new element to add as second.
156 addToFM_C :: (Ord key OUTPUTABLE_key) => (elt -> elt -> elt)
157 -> FiniteMap key elt -> key -> elt
160 -- | A list version of 'addToFM_C'. The elements are added in the
161 -- order given in the list.
162 addListToFM_C :: (Ord key OUTPUTABLE_key) => (elt -> elt -> elt)
163 -> FiniteMap key elt -> [(key,elt)]
166 -- | Deletes an element from a 'FiniteMap'. If there is no element with
167 -- the specified key, then the original 'FiniteMap' is returned.
168 delFromFM :: (Ord key OUTPUTABLE_key) => FiniteMap key elt -> key -> FiniteMap key elt
170 -- | List version of 'delFromFM'.
171 delListFromFM :: (Ord key OUTPUTABLE_key) => FiniteMap key elt -> [key] -> FiniteMap key elt
173 -- | Combine two 'FiniteMap's. Mappings in the second argument shadow
174 -- those in the first.
175 plusFM :: (Ord key OUTPUTABLE_key) => FiniteMap key elt -> FiniteMap key elt
178 -- | Combine two 'FiniteMap's. The specified combination function is
179 -- used to calculate the new value when there are two elements with
181 plusFM_C :: (Ord key OUTPUTABLE_key) => (elt -> elt -> elt)
182 -> FiniteMap key elt -> FiniteMap key elt -> FiniteMap key elt
184 -- | @(minusFM a1 a2)@ deletes from @a1@ any mappings which are bound in @a2@
185 minusFM :: (Ord key OUTPUTABLE_key) => FiniteMap key elt1 -> FiniteMap key elt2 -> FiniteMap key elt1
187 -- | @(intersectFM a1 a2)@ returns a new 'FiniteMap' containing
188 -- mappings from @a1@ for which @a2@ also has a mapping with the same
190 intersectFM :: (Ord key OUTPUTABLE_key) => FiniteMap key elt -> FiniteMap key elt -> FiniteMap key elt
192 -- | Returns the intersection of two mappings, using the specified
193 -- combination function to combine values.
194 intersectFM_C :: (Ord key OUTPUTABLE_key) => (elt1 -> elt2 -> elt3)
195 -> FiniteMap key elt1 -> FiniteMap key elt2 -> FiniteMap key elt3
197 -- MAPPING, FOLDING, FILTERING
198 foldFM :: (key -> elt -> a -> a) -> a -> FiniteMap key elt -> a
199 mapFM :: (key -> elt1 -> elt2) -> FiniteMap key elt1 -> FiniteMap key elt2
200 filterFM :: (Ord key OUTPUTABLE_key) => (key -> elt -> Bool)
201 -> FiniteMap key elt -> FiniteMap key elt
204 sizeFM :: FiniteMap key elt -> Int
205 isEmptyFM :: FiniteMap key elt -> Bool
207 -- | Returns 'True' if the specified @key@ has a mapping in this
208 -- 'FiniteMap', or 'False' otherwise.
209 elemFM :: (Ord key OUTPUTABLE_key) => key -> FiniteMap key elt -> Bool
211 -- | Looks up a key in a 'FiniteMap', returning @'Just' v@ if the key
212 -- was found with value @v@, or 'Nothing' otherwise.
213 lookupFM :: (Ord key OUTPUTABLE_key) => FiniteMap key elt -> key -> Maybe elt
215 -- | Looks up a key in a 'FiniteMap', returning @elt@ if the specified
216 -- @key@ was not found.
218 :: (Ord key OUTPUTABLE_key) => FiniteMap key elt -> elt -> key -> elt
219 -- lookupWithDefaultFM supplies a "default" elt
220 -- to return for an unmapped key
224 -- | Convert a 'FiniteMap' to a @[(key, elt)]@ sorted by 'Ord' key
226 fmToList :: FiniteMap key elt -> [(key,elt)]
228 -- | Extract the keys from a 'FiniteMap', in the order of the keys, so
230 -- > keysFM == map fst . fmToList
232 keysFM :: FiniteMap key elt -> [key]
234 -- | Extract the elements from a 'FiniteMap', in the order of the keys, so
236 -- > eltsFM == map snd . fmToList
238 eltsFM :: FiniteMap key elt -> [elt]
240 -- ---------------------------------------------------------------------------
241 -- The @FiniteMap@ data type, and building of same
243 -- Invariants about @FiniteMap@:
245 -- * all keys in a FiniteMap are distinct
247 -- * all keys in left subtree are $<$ key in Branch and
248 -- all keys in right subtree are $>$ key in Branch
250 -- * size field of a Branch gives number of Branch nodes in the tree
252 -- * size of left subtree is differs from size of right subtree by a
253 -- factor of at most \tr{sIZE_RATIO}
255 -- | A mapping from @key@s to @elt@s.
256 data FiniteMap key elt
258 | Branch key elt -- Key and elt stored here
259 IF_GHC(Int#,Int{-STRICT-}) -- Size >= 1
260 (FiniteMap key elt) -- Children
267 = Branch bottom bottom IF_GHC(0#,0) bottom bottom
269 bottom = panic "emptyFM"
272 -- #define EmptyFM (Branch _ _ IF_GHC(0#,0) _ _)
274 unitFM key elt = Branch key elt IF_GHC(1#,1) emptyFM emptyFM
276 listToFM = addListToFM emptyFM
279 bagToFM = foldBag plusFM (\ (k,v) -> unitFM k v) emptyFM
282 instance (Show k, Show e) => Show (FiniteMap k e) where
283 showsPrec p m = showsPrec p (fmToList m)
285 instance Functor (FiniteMap k) where
286 fmap f = mapFM (const f)
288 -- ---------------------------------------------------------------------------
289 -- Adding to and deleting from @FiniteMaps@
291 addToFM fm key elt = addToFM_C (\ old new -> new) fm key elt
293 addToFM_C combiner EmptyFM key elt = unitFM key elt
294 addToFM_C combiner (Branch key elt size fm_l fm_r) new_key new_elt
295 #ifdef __GLASGOW_HASKELL__
296 = case _tagCmp new_key key of
297 _LT -> mkBalBranch key elt (addToFM_C combiner fm_l new_key new_elt) fm_r
298 _GT -> mkBalBranch key elt fm_l (addToFM_C combiner fm_r new_key new_elt)
299 _EQ -> Branch new_key (combiner elt new_elt) size fm_l fm_r
301 | new_key < key = mkBalBranch key elt (addToFM_C combiner fm_l new_key new_elt) fm_r
302 | new_key > key = mkBalBranch key elt fm_l (addToFM_C combiner fm_r new_key new_elt)
303 | otherwise = Branch new_key (combiner elt new_elt) size fm_l fm_r
306 addListToFM fm key_elt_pairs = addListToFM_C (\ old new -> new) fm key_elt_pairs
308 addListToFM_C combiner fm key_elt_pairs
309 = foldl add fm key_elt_pairs -- foldl adds from the left
311 add fmap (key,elt) = addToFM_C combiner fmap key elt
314 delFromFM EmptyFM del_key = emptyFM
315 delFromFM (Branch key elt size fm_l fm_r) del_key
316 #if __GLASGOW_HASKELL__
317 = case _tagCmp del_key key of
318 _GT -> mkBalBranch key elt fm_l (delFromFM fm_r del_key)
319 _LT -> mkBalBranch key elt (delFromFM fm_l del_key) fm_r
320 _EQ -> glueBal fm_l fm_r
323 = mkBalBranch key elt fm_l (delFromFM fm_r del_key)
326 = mkBalBranch key elt (delFromFM fm_l del_key) fm_r
332 delListFromFM fm keys = foldl delFromFM fm keys
334 -- ---------------------------------------------------------------------------
335 -- Combining @FiniteMaps@
337 plusFM_C combiner EmptyFM fm2 = fm2
338 plusFM_C combiner fm1 EmptyFM = fm1
339 plusFM_C combiner fm1 (Branch split_key elt2 _ left right)
340 = mkVBalBranch split_key new_elt
341 (plusFM_C combiner lts left)
342 (plusFM_C combiner gts right)
344 lts = splitLT fm1 split_key
345 gts = splitGT fm1 split_key
346 new_elt = case lookupFM fm1 split_key of
348 Just elt1 -> combiner elt1 elt2
350 -- It's worth doing plusFM specially, because we don't need
351 -- to do the lookup in fm1.
353 plusFM EmptyFM fm2 = fm2
354 plusFM fm1 EmptyFM = fm1
355 plusFM fm1 (Branch split_key elt1 _ left right)
356 = mkVBalBranch split_key elt1 (plusFM lts left) (plusFM gts right)
358 lts = splitLT fm1 split_key
359 gts = splitGT fm1 split_key
361 minusFM EmptyFM fm2 = emptyFM
362 minusFM fm1 EmptyFM = fm1
363 minusFM fm1 (Branch split_key elt _ left right)
364 = glueVBal (minusFM lts left) (minusFM gts right)
365 -- The two can be way different, so we need glueVBal
367 lts = splitLT fm1 split_key -- NB gt and lt, so the equal ones
368 gts = splitGT fm1 split_key -- are not in either.
370 intersectFM fm1 fm2 = intersectFM_C (\ left right -> right) fm1 fm2
372 intersectFM_C combiner fm1 EmptyFM = emptyFM
373 intersectFM_C combiner EmptyFM fm2 = emptyFM
374 intersectFM_C combiner fm1 (Branch split_key elt2 _ left right)
376 | isJust maybe_elt1 -- split_elt *is* in intersection
377 = mkVBalBranch split_key (combiner elt1 elt2) (intersectFM_C combiner lts left)
378 (intersectFM_C combiner gts right)
380 | otherwise -- split_elt is *not* in intersection
381 = glueVBal (intersectFM_C combiner lts left) (intersectFM_C combiner gts right)
384 lts = splitLT fm1 split_key -- NB gt and lt, so the equal ones
385 gts = splitGT fm1 split_key -- are not in either.
387 maybe_elt1 = lookupFM fm1 split_key
388 Just elt1 = maybe_elt1
391 -- ---------------------------------------------------------------------------
392 -- Mapping, folding, and filtering with @FiniteMaps@
394 foldFM k z EmptyFM = z
395 foldFM k z (Branch key elt _ fm_l fm_r)
396 = foldFM k (k key elt (foldFM k z fm_r)) fm_l
398 mapFM f EmptyFM = emptyFM
399 mapFM f (Branch key elt size fm_l fm_r)
400 = Branch key (f key elt) size (mapFM f fm_l) (mapFM f fm_r)
402 filterFM p EmptyFM = emptyFM
403 filterFM p (Branch key elt _ fm_l fm_r)
404 | p key elt -- Keep the item
405 = mkVBalBranch key elt (filterFM p fm_l) (filterFM p fm_r)
407 | otherwise -- Drop the item
408 = glueVBal (filterFM p fm_l) (filterFM p fm_r)
411 -- ---------------------------------------------------------------------------
412 -- Interrogating @FiniteMaps@
414 --{-# INLINE sizeFM #-}
416 sizeFM (Branch _ _ size _ _) = IF_GHC(I# size, size)
418 isEmptyFM fm = sizeFM fm == 0
420 lookupFM EmptyFM key = Nothing
421 lookupFM (Branch key elt _ fm_l fm_r) key_to_find
422 #if __GLASGOW_HASKELL__
423 = case _tagCmp key_to_find key of
424 _LT -> lookupFM fm_l key_to_find
425 _GT -> lookupFM fm_r key_to_find
428 | key_to_find < key = lookupFM fm_l key_to_find
429 | key_to_find > key = lookupFM fm_r key_to_find
430 | otherwise = Just elt
434 = case (lookupFM fm key) of { Nothing -> False; Just elt -> True }
436 lookupWithDefaultFM fm deflt key
437 = case (lookupFM fm key) of { Nothing -> deflt; Just elt -> elt }
440 -- ---------------------------------------------------------------------------
441 -- Listifying @FiniteMaps@
443 fmToList fm = foldFM (\ key elt rest -> (key,elt) : rest) [] fm
444 keysFM fm = foldFM (\ key elt rest -> key : rest) [] fm
445 eltsFM fm = foldFM (\ key elt rest -> elt : rest) [] fm
448 -- ---------------------------------------------------------------------------
449 -- Bulk operations on all keys >= or <= a certain threshold
451 -- | Fold through all elements greater than or equal to the supplied key,
452 -- in increasing order.
453 foldFM_GE :: Ord key => (key -> elt -> a -> a) -> a -> key ->
454 FiniteMap key elt -> a
456 foldFM_GE k z fr EmptyFM = z
457 foldFM_GE k z fr (Branch key elt _ fm_l fm_r)
458 | key >= fr = foldFM_GE k (k key elt (foldFM_GE k z fr fm_r)) fr fm_l
459 | otherwise = foldFM_GE k z fr fm_r
461 -- | List elements greater than or equal to the supplied key, in increasing
463 fmToList_GE :: Ord key => FiniteMap key elt -> key -> [(key,elt)]
464 fmToList_GE fm fr = foldFM_GE (\ key elt rest -> (key,elt) : rest) [] fr fm
466 -- | List keys greater than or equal to the supplied key, in increasing order
467 keysFM_GE :: Ord key => FiniteMap key elt -> key -> [key]
468 keysFM_GE fm fr = foldFM_GE (\ key elt rest -> key : rest) [] fr fm
470 -- | List elements corresponding to keys greater than or equal to the supplied
471 -- key, in increasing order of key.
472 eltsFM_GE :: Ord key => FiniteMap key elt -> key -> [elt]
473 eltsFM_GE fm fr = foldFM_GE (\ key elt rest -> elt : rest) [] fr fm
475 -- | Fold through all elements less than or equal to the supplied key,
476 -- in decreasing order.
477 foldFM_LE :: Ord key => (key -> elt -> a -> a) -> a -> key ->
478 FiniteMap key elt -> a
479 foldFM_LE k z fr EmptyFM = z
480 foldFM_LE k z fr (Branch key elt _ fm_l fm_r)
481 | key <= fr = foldFM_LE k (k key elt (foldFM_LE k z fr fm_l)) fr fm_r
482 | otherwise = foldFM_LE k z fr fm_l
484 -- | List elements greater than or equal to the supplied key, in decreasing
486 fmToList_LE :: Ord key => FiniteMap key elt -> key -> [(key,elt)]
487 fmToList_LE fm fr = foldFM_LE (\ key elt rest -> (key,elt) : rest) [] fr fm
489 -- | List keys greater than or equal to the supplied key, in decreasing order
490 keysFM_LE :: Ord key => FiniteMap key elt -> key -> [key]
491 keysFM_LE fm fr = foldFM_LE (\ key elt rest -> key : rest) [] fr fm
493 -- | List elements corresponding to keys greater than or equal to the supplied
494 -- key, in decreasing order of key.
495 eltsFM_LE :: Ord key => FiniteMap key elt -> key -> [elt]
496 eltsFM_LE fm fr = foldFM_LE (\ key elt rest -> elt : rest) [] fr fm
498 -- ---------------------------------------------------------------------------
499 -- Getting minimum and maximum key out.
500 -- ---------------------------------------------------------------------------
502 -- | Extract minimum key, or Nothing if the map is empty.
503 minFM :: Ord key => FiniteMap key elt -> Maybe key
504 minFM EmptyFM = Nothing
505 minFM (Branch key _ _ fm_l _) =
508 Just key1 -> Just key1
510 -- | Extract maximum key, or Nothing if the map is empty.
511 maxFM :: Ord key => FiniteMap key elt -> Maybe key
512 maxFM EmptyFM = Nothing
513 maxFM (Branch key _ _ _ fm_r) =
516 Just key1 -> Just key1
519 -- ---------------------------------------------------------------------------
520 -- The implementation of balancing
522 -- Basic construction of a @FiniteMap@:
524 -- @mkBranch@ simply gets the size component right. This is the ONLY
525 -- (non-trivial) place the Branch object is built, so the ASSERTion
526 -- recursively checks consistency. (The trivial use of Branch is in
532 mkBranch :: (Ord key OUTPUTABLE_key) -- Used for the assertion checking only
535 -> FiniteMap key elt -> FiniteMap key elt
538 mkBranch which key elt fm_l fm_r
539 = --ASSERT( left_ok && right_ok && balance_ok )
540 #if defined(COMPILING_GHC) && defined(DEBUG_FINITEMAPS)
541 if not ( left_ok && right_ok && balance_ok ) then
542 pprPanic ("mkBranch:"++show which) (ppAboves [ppr PprDebug [left_ok, right_ok, balance_ok],
549 result = Branch key elt (unbox (1 + left_size + right_size)) fm_l fm_r
551 -- if sizeFM result <= 8 then
554 -- pprTrace ("mkBranch:"++(show which)) (ppr PprDebug result) (
558 left_ok = case fm_l of
560 Branch left_key _ _ _ _ -> let
561 biggest_left_key = fst (findMax fm_l)
563 biggest_left_key < key
564 right_ok = case fm_r of
566 Branch right_key _ _ _ _ -> let
567 smallest_right_key = fst (findMin fm_r)
569 key < smallest_right_key
570 balance_ok = True -- sigh
573 = -- Both subtrees have one or no elements...
574 (left_size + right_size <= 1)
575 -- NO || left_size == 0 -- ???
576 -- NO || right_size == 0 -- ???
577 -- ... or the number of elements in a subtree does not exceed
578 -- sIZE_RATIO times the number of elements in the other subtree
579 || (left_size * sIZE_RATIO >= right_size &&
580 right_size * sIZE_RATIO >= left_size)
583 left_size = sizeFM fm_l
584 right_size = sizeFM fm_r
586 #if __GLASGOW_HASKELL__
588 unbox (I# size) = size
595 -- ---------------------------------------------------------------------------
596 -- {\em Balanced} construction of a @FiniteMap@
598 -- @mkBalBranch@ rebalances, assuming that the subtrees aren't too far
601 mkBalBranch :: (Ord key OUTPUTABLE_key)
603 -> FiniteMap key elt -> FiniteMap key elt
606 mkBalBranch key elt fm_L fm_R
608 | size_l + size_r < 2
609 = mkBranch 1{-which-} key elt fm_L fm_R
611 | size_r > sIZE_RATIO * size_l -- Right tree too big
613 Branch _ _ _ fm_rl fm_rr
614 | sizeFM fm_rl < 2 * sizeFM fm_rr -> single_L fm_L fm_R
615 | otherwise -> double_L fm_L fm_R
616 -- Other case impossible
618 | size_l > sIZE_RATIO * size_r -- Left tree too big
620 Branch _ _ _ fm_ll fm_lr
621 | sizeFM fm_lr < 2 * sizeFM fm_ll -> single_R fm_L fm_R
622 | otherwise -> double_R fm_L fm_R
623 -- Other case impossible
625 | otherwise -- No imbalance
626 = mkBranch 2{-which-} key elt fm_L fm_R
632 single_L fm_l (Branch key_r elt_r _ fm_rl fm_rr)
633 = mkBranch 3{-which-} key_r elt_r (mkBranch 4{-which-} key elt fm_l fm_rl) fm_rr
635 double_L fm_l (Branch key_r elt_r _ (Branch key_rl elt_rl _ fm_rll fm_rlr) fm_rr)
636 = mkBranch 5{-which-} key_rl elt_rl (mkBranch 6{-which-} key elt fm_l fm_rll)
637 (mkBranch 7{-which-} key_r elt_r fm_rlr fm_rr)
639 single_R (Branch key_l elt_l _ fm_ll fm_lr) fm_r
640 = mkBranch 8{-which-} key_l elt_l fm_ll (mkBranch 9{-which-} key elt fm_lr fm_r)
642 double_R (Branch key_l elt_l _ fm_ll (Branch key_lr elt_lr _ fm_lrl fm_lrr)) fm_r
643 = mkBranch 10{-which-} key_lr elt_lr (mkBranch 11{-which-} key_l elt_l fm_ll fm_lrl)
644 (mkBranch 12{-which-} key elt fm_lrr fm_r)
647 mkVBalBranch :: (Ord key OUTPUTABLE_key)
649 -> FiniteMap key elt -> FiniteMap key elt
652 -- Assert: in any call to (mkVBalBranch_C comb key elt l r),
653 -- (a) all keys in l are < all keys in r
654 -- (b) all keys in l are < key
655 -- (c) all keys in r are > key
657 mkVBalBranch key elt EmptyFM fm_r = addToFM fm_r key elt
658 mkVBalBranch key elt fm_l EmptyFM = addToFM fm_l key elt
660 mkVBalBranch key elt fm_l@(Branch key_l elt_l _ fm_ll fm_lr)
661 fm_r@(Branch key_r elt_r _ fm_rl fm_rr)
662 | sIZE_RATIO * size_l < size_r
663 = mkBalBranch key_r elt_r (mkVBalBranch key elt fm_l fm_rl) fm_rr
665 | sIZE_RATIO * size_r < size_l
666 = mkBalBranch key_l elt_l fm_ll (mkVBalBranch key elt fm_lr fm_r)
669 = mkBranch 13{-which-} key elt fm_l fm_r
675 -- ---------------------------------------------------------------------------
676 -- Gluing two trees together
678 -- @glueBal@ assumes its two arguments aren't too far out of whack, just
679 -- like @mkBalBranch@. But: all keys in first arg are $<$ all keys in
682 glueBal :: (Ord key OUTPUTABLE_key)
683 => FiniteMap key elt -> FiniteMap key elt
686 glueBal EmptyFM fm2 = fm2
687 glueBal fm1 EmptyFM = fm1
689 -- The case analysis here (absent in Adams' program) is really to deal
690 -- with the case where fm2 is a singleton. Then deleting the minimum means
691 -- we pass an empty tree to mkBalBranch, which breaks its invariant.
692 | sizeFM fm2 > sizeFM fm1
693 = mkBalBranch mid_key2 mid_elt2 fm1 (deleteMin fm2)
696 = mkBalBranch mid_key1 mid_elt1 (deleteMax fm1) fm2
698 (mid_key1, mid_elt1) = findMax fm1
699 (mid_key2, mid_elt2) = findMin fm2
701 -- @glueVBal@ copes with arguments which can be of any size.
702 -- But: all keys in first arg are $<$ all keys in second.
704 glueVBal :: (Ord key OUTPUTABLE_key)
705 => FiniteMap key elt -> FiniteMap key elt
708 glueVBal EmptyFM fm2 = fm2
709 glueVBal fm1 EmptyFM = fm1
710 glueVBal fm_l@(Branch key_l elt_l _ fm_ll fm_lr)
711 fm_r@(Branch key_r elt_r _ fm_rl fm_rr)
712 | sIZE_RATIO * size_l < size_r
713 = mkBalBranch key_r elt_r (glueVBal fm_l fm_rl) fm_rr
715 | sIZE_RATIO * size_r < size_l
716 = mkBalBranch key_l elt_l fm_ll (glueVBal fm_lr fm_r)
718 | otherwise -- We now need the same two cases as in glueBal above.
725 -- ---------------------------------------------------------------------------
728 splitLT, splitGT :: (Ord key OUTPUTABLE_key) => FiniteMap key elt -> key -> FiniteMap key elt
730 -- splitLT fm split_key = fm restricted to keys < split_key
731 -- splitGT fm split_key = fm restricted to keys > split_key
733 splitLT EmptyFM split_key = emptyFM
734 splitLT (Branch key elt _ fm_l fm_r) split_key
735 #if __GLASGOW_HASKELL__
736 = case _tagCmp split_key key of
737 _LT -> splitLT fm_l split_key
738 _GT -> mkVBalBranch key elt fm_l (splitLT fm_r split_key)
741 | split_key < key = splitLT fm_l split_key
742 | split_key > key = mkVBalBranch key elt fm_l (splitLT fm_r split_key)
746 splitGT EmptyFM split_key = emptyFM
747 splitGT (Branch key elt _ fm_l fm_r) split_key
748 #if __GLASGOW_HASKELL__
749 = case _tagCmp split_key key of
750 _GT -> splitGT fm_r split_key
751 _LT -> mkVBalBranch key elt (splitGT fm_l split_key) fm_r
754 | split_key > key = splitGT fm_r split_key
755 | split_key < key = mkVBalBranch key elt (splitGT fm_l split_key) fm_r
759 findMin :: FiniteMap key elt -> (key,elt)
760 findMin (Branch key elt _ EmptyFM _) = (key,elt)
761 findMin (Branch key elt _ fm_l _) = findMin fm_l
763 deleteMin :: (Ord key OUTPUTABLE_key) => FiniteMap key elt -> FiniteMap key elt
764 deleteMin (Branch key elt _ EmptyFM fm_r) = fm_r
765 deleteMin (Branch key elt _ fm_l fm_r) = mkBalBranch key elt (deleteMin fm_l) fm_r
767 findMax :: FiniteMap key elt -> (key,elt)
768 findMax (Branch key elt _ _ EmptyFM) = (key,elt)
769 findMax (Branch key elt _ _ fm_r) = findMax fm_r
771 deleteMax :: (Ord key OUTPUTABLE_key) => FiniteMap key elt -> FiniteMap key elt
772 deleteMax (Branch key elt _ fm_l EmptyFM) = fm_l
773 deleteMax (Branch key elt _ fm_l fm_r) = mkBalBranch key elt fm_l (deleteMax fm_r)
776 -- ---------------------------------------------------------------------------
779 #if defined(COMPILING_GHC) && defined(DEBUG_FINITEMAPS)
781 instance (Outputable key) => Outputable (FiniteMap key elt) where
782 ppr sty fm = pprX sty fm
784 pprX sty EmptyFM = ppChar '!'
785 pprX sty (Branch key elt sz fm_l fm_r)
786 = ppBesides [ppLparen, pprX sty fm_l, ppSP,
787 ppr sty key, ppSP, ppInt (IF_GHC(I# sz, sz)), ppSP,
788 pprX sty fm_r, ppRparen]
791 #ifndef COMPILING_GHC
792 instance (Eq key, Eq elt) => Eq (FiniteMap key elt) where
793 fm_1 == fm_2 = (sizeFM fm_1 == sizeFM fm_2) && -- quick test
794 (fmToList fm_1 == fmToList fm_2)
796 {- NO: not clear what The Right Thing to do is:
797 instance (Ord key, Ord elt) => Ord (FiniteMap key elt) where
798 fm_1 <= fm_2 = (sizeFM fm_1 <= sizeFM fm_2) && -- quick test
799 (fmToList fm_1 <= fmToList fm_2)
803 -- ---------------------------------------------------------------------------
804 -- Efficiency pragmas for GHC
806 -- When the FiniteMap module is used in GHC, we specialise it for
807 -- \tr{Uniques}, for dastardly efficiency reasons.
809 #if defined(COMPILING_GHC) && __GLASGOW_HASKELL__ && !defined(REALLY_HASKELL_1_3)
811 {-# SPECIALIZE addListToFM
812 :: FiniteMap (FAST_STRING, FAST_STRING) elt -> [((FAST_STRING, FAST_STRING),elt)] -> FiniteMap (FAST_STRING, FAST_STRING) elt
813 , FiniteMap RdrName elt -> [(RdrName,elt)] -> FiniteMap RdrName elt
814 IF_NCG(COMMA FiniteMap Reg elt -> [(Reg COMMA elt)] -> FiniteMap Reg elt)
816 {-# SPECIALIZE addListToFM_C
817 :: (elt -> elt -> elt) -> FiniteMap TyCon elt -> [(TyCon,elt)] -> FiniteMap TyCon elt
818 , (elt -> elt -> elt) -> FiniteMap FAST_STRING elt -> [(FAST_STRING,elt)] -> FiniteMap FAST_STRING elt
819 IF_NCG(COMMA (elt -> elt -> elt) -> FiniteMap Reg elt -> [(Reg COMMA elt)] -> FiniteMap Reg elt)
821 {-# SPECIALIZE addToFM
822 :: FiniteMap CLabel elt -> CLabel -> elt -> FiniteMap CLabel elt
823 , FiniteMap FAST_STRING elt -> FAST_STRING -> elt -> FiniteMap FAST_STRING elt
824 , FiniteMap (FAST_STRING, FAST_STRING) elt -> (FAST_STRING, FAST_STRING) -> elt -> FiniteMap (FAST_STRING, FAST_STRING) elt
825 , FiniteMap RdrName elt -> RdrName -> elt -> FiniteMap RdrName elt
826 , FiniteMap OrigName elt -> OrigName -> elt -> FiniteMap OrigName elt
827 IF_NCG(COMMA FiniteMap Reg elt -> Reg -> elt -> FiniteMap Reg elt)
829 {-# SPECIALIZE addToFM_C
830 :: (elt -> elt -> elt) -> FiniteMap (RdrName, RdrName) elt -> (RdrName, RdrName) -> elt -> FiniteMap (RdrName, RdrName) elt
831 , (elt -> elt -> elt) -> FiniteMap (OrigName, OrigName) elt -> (OrigName, OrigName) -> elt -> FiniteMap (OrigName, OrigName) elt
832 , (elt -> elt -> elt) -> FiniteMap FAST_STRING elt -> FAST_STRING -> elt -> FiniteMap FAST_STRING elt
833 IF_NCG(COMMA (elt -> elt -> elt) -> FiniteMap Reg elt -> Reg -> elt -> FiniteMap Reg elt)
835 {-# SPECIALIZE bagToFM
836 :: Bag (FAST_STRING,elt) -> FiniteMap FAST_STRING elt
838 {-# SPECIALIZE delListFromFM
839 :: FiniteMap RdrName elt -> [RdrName] -> FiniteMap RdrName elt
840 , FiniteMap OrigName elt -> [OrigName] -> FiniteMap OrigName elt
841 , FiniteMap FAST_STRING elt -> [FAST_STRING] -> FiniteMap FAST_STRING elt
842 IF_NCG(COMMA FiniteMap Reg elt -> [Reg] -> FiniteMap Reg elt)
844 {-# SPECIALIZE listToFM
845 :: [([Char],elt)] -> FiniteMap [Char] elt
846 , [(FAST_STRING,elt)] -> FiniteMap FAST_STRING elt
847 , [((FAST_STRING,FAST_STRING),elt)] -> FiniteMap (FAST_STRING, FAST_STRING) elt
848 , [(OrigName,elt)] -> FiniteMap OrigName elt
849 IF_NCG(COMMA [(Reg COMMA elt)] -> FiniteMap Reg elt)
851 {-# SPECIALIZE lookupFM
852 :: FiniteMap CLabel elt -> CLabel -> Maybe elt
853 , FiniteMap [Char] elt -> [Char] -> Maybe elt
854 , FiniteMap FAST_STRING elt -> FAST_STRING -> Maybe elt
855 , FiniteMap (FAST_STRING,FAST_STRING) elt -> (FAST_STRING,FAST_STRING) -> Maybe elt
856 , FiniteMap OrigName elt -> OrigName -> Maybe elt
857 , FiniteMap (OrigName,OrigName) elt -> (OrigName,OrigName) -> Maybe elt
858 , FiniteMap RdrName elt -> RdrName -> Maybe elt
859 , FiniteMap (RdrName,RdrName) elt -> (RdrName,RdrName) -> Maybe elt
860 IF_NCG(COMMA FiniteMap Reg elt -> Reg -> Maybe elt)
862 {-# SPECIALIZE lookupWithDefaultFM
863 :: FiniteMap FAST_STRING elt -> elt -> FAST_STRING -> elt
864 IF_NCG(COMMA FiniteMap Reg elt -> elt -> Reg -> elt)
866 {-# SPECIALIZE plusFM
867 :: FiniteMap RdrName elt -> FiniteMap RdrName elt -> FiniteMap RdrName elt
868 , FiniteMap OrigName elt -> FiniteMap OrigName elt -> FiniteMap OrigName elt
869 , FiniteMap FAST_STRING elt -> FiniteMap FAST_STRING elt -> FiniteMap FAST_STRING elt
870 IF_NCG(COMMA FiniteMap Reg elt -> FiniteMap Reg elt -> FiniteMap Reg elt)
872 {-# SPECIALIZE plusFM_C
873 :: (elt -> elt -> elt) -> FiniteMap FAST_STRING elt -> FiniteMap FAST_STRING elt -> FiniteMap FAST_STRING elt
874 IF_NCG(COMMA (elt -> elt -> elt) -> FiniteMap Reg elt -> FiniteMap Reg elt -> FiniteMap Reg elt)
877 #endif /* compiling for GHC */