2 % (c) The AQUA Project, Glasgow University, 1994-1996
4 \section[UniqFM]{Specialised finite maps, for things with @Uniques@}
6 Based on @FiniteMaps@ (as you would expect).
8 Basically, the things need to be in class @Uniquable@, and we use the
9 @uniqueOf@ method to grab their @Uniques@.
11 (A similar thing to @UniqSet@, as opposed to @Set@.)
14 #if defined(COMPILING_GHC)
15 #include "HsVersions.h"
16 #define IF_NOT_GHC(a) {--}
18 #define ASSERT(e) {--}
19 #define IF_NOT_GHC(a) a
23 UniqFM, -- abstract type
24 Uniquable(..), -- class to go with it
34 addListToUFM_Directly,
35 IF_NOT_GHC(addToUFM_C COMMA)
43 IF_NOT_GHC(intersectUFM_C COMMA)
44 IF_NOT_GHC(foldUFM COMMA)
49 lookupUFM, lookupUFM_Directly,
50 lookupWithDefaultUFM, lookupWithDefaultUFM_Directly,
54 -- to make the interface self-sufficient
57 #if defined(COMPILING_GHC)
61 import Unique ( Unique, u2i, mkUniqueGrimily )
63 --import Outputable ( Outputable(..), ExportFlag )
64 import Pretty ( Pretty(..), PrettyRep )
65 import PprStyle ( PprStyle )
66 import SrcLoc ( SrcLoc )
68 #if ! OMIT_NATIVE_CODEGEN
71 #define IF_NCG(a) {--}
75 %************************************************************************
77 \subsection{The @UniqFM@ type, and signatures for the functions}
79 %************************************************************************
81 We use @FiniteMaps@, with a (@uniqueOf@-able) @Unique@ as ``key''.
84 emptyUFM :: UniqFM elt
85 isNullUFM :: UniqFM elt -> Bool
86 unitUFM :: Uniquable key => key -> elt -> UniqFM elt
87 unitDirectlyUFM -- got the Unique already
88 :: Unique -> elt -> UniqFM elt
89 listToUFM :: Uniquable key => [(key,elt)] -> UniqFM elt
91 :: [(Unique, elt)] -> UniqFM elt
93 addToUFM :: Uniquable key => UniqFM elt -> key -> elt -> UniqFM elt
94 addListToUFM :: Uniquable key => UniqFM elt -> [(key,elt)] -> UniqFM elt
96 :: UniqFM elt -> Unique -> elt -> UniqFM elt
98 addToUFM_C :: Uniquable key => (elt -> elt -> elt)
99 -> UniqFM elt -> key -> elt -> UniqFM elt
100 addListToUFM_C :: Uniquable key => (elt -> elt -> elt)
101 -> UniqFM elt -> [(key,elt)]
104 delFromUFM :: Uniquable key => UniqFM elt -> key -> UniqFM elt
105 delListFromUFM :: Uniquable key => UniqFM elt -> [key] -> UniqFM elt
107 plusUFM :: UniqFM elt -> UniqFM elt -> UniqFM elt
109 plusUFM_C :: (elt -> elt -> elt)
110 -> UniqFM elt -> UniqFM elt -> UniqFM elt
112 minusUFM :: UniqFM elt -> UniqFM elt -> UniqFM elt
114 intersectUFM :: UniqFM elt -> UniqFM elt -> UniqFM elt
115 intersectUFM_C :: (elt -> elt -> elt)
116 -> UniqFM elt -> UniqFM elt -> UniqFM elt
117 foldUFM :: (elt -> a -> a) -> a -> UniqFM elt -> a
118 mapUFM :: (elt1 -> elt2) -> UniqFM elt1 -> UniqFM elt2
119 filterUFM :: (elt -> Bool) -> UniqFM elt -> UniqFM elt
121 sizeUFM :: UniqFM elt -> Int
123 lookupUFM :: Uniquable key => UniqFM elt -> key -> Maybe elt
124 lookupUFM_Directly -- when you've got the Unique already
125 :: UniqFM elt -> Unique -> Maybe elt
127 :: Uniquable key => UniqFM elt -> elt -> key -> elt
128 lookupWithDefaultUFM_Directly
129 :: UniqFM elt -> elt -> Unique -> elt
131 eltsUFM :: UniqFM elt -> [elt]
132 ufmToList :: UniqFM elt -> [(Unique, elt)]
135 %************************************************************************
137 \subsection{The @IdFinMap@ and @TyVarFinMap@ specialisations for Ids/TyVars}
139 %************************************************************************
144 type IdFinMap elt = UniqFM elt
145 type TyVarFinMap elt = UniqFM elt
146 type NameFinMap elt = UniqFM elt
147 type RegFinMap elt = UniqFM elt
149 #ifdef __GLASGOW_HASKELL__
150 -- I don't think HBC was too happy about this (WDP 94/10)
153 unitUFM :: Id -> elt -> IdFinMap elt,
154 TyVar -> elt -> TyVarFinMap elt,
155 Name -> elt -> NameFinMap elt
156 IF_NCG(COMMA Reg -> elt -> RegFinMap elt)
159 listToUFM :: [(Id, elt)] -> IdFinMap elt,
160 [(TyVar,elt)] -> TyVarFinMap elt,
161 [(Name, elt)] -> NameFinMap elt
162 IF_NCG(COMMA [(Reg COMMA elt)] -> RegFinMap elt)
165 addToUFM :: IdFinMap elt -> Id -> elt -> IdFinMap elt,
166 TyVarFinMap elt -> TyVar -> elt -> TyVarFinMap elt,
167 NameFinMap elt -> Name -> elt -> NameFinMap elt
168 IF_NCG(COMMA RegFinMap elt -> Reg -> elt -> RegFinMap elt)
171 addListToUFM :: IdFinMap elt -> [(Id, elt)] -> IdFinMap elt,
172 TyVarFinMap elt -> [(TyVar,elt)] -> TyVarFinMap elt,
173 NameFinMap elt -> [(Name,elt)] -> NameFinMap elt
174 IF_NCG(COMMA RegFinMap elt -> [(Reg COMMA elt)] -> RegFinMap elt)
177 addToUFM_C :: (elt -> elt -> elt)
178 -> IdFinMap elt -> Id -> elt -> IdFinMap elt,
180 -> TyVarFinMap elt -> TyVar -> elt -> TyVarFinMap elt,
182 -> NameFinMap elt -> Name -> elt -> NameFinMap elt
183 IF_NCG(COMMA (elt -> elt -> elt)
184 -> RegFinMap elt -> Reg -> elt -> RegFinMap elt)
187 addListToUFM_C :: (elt -> elt -> elt)
188 -> IdFinMap elt -> [(Id,elt)] -> IdFinMap elt,
190 -> TyVarFinMap elt -> [(TyVar,elt)] -> TyVarFinMap elt,
192 -> NameFinMap elt -> [(Name,elt)] -> NameFinMap elt
193 IF_NCG(COMMA (elt -> elt -> elt)
194 -> RegFinMap elt -> [(Reg COMMA elt)] -> RegFinMap elt)
197 delFromUFM :: IdFinMap elt -> Id -> IdFinMap elt,
198 TyVarFinMap elt -> TyVar -> TyVarFinMap elt,
199 NameFinMap elt -> Name -> NameFinMap elt
200 IF_NCG(COMMA RegFinMap elt -> Reg -> RegFinMap elt)
203 delListFromUFM :: IdFinMap elt -> [Id] -> IdFinMap elt,
204 TyVarFinMap elt -> [TyVar] -> TyVarFinMap elt,
205 NameFinMap elt -> [Name] -> NameFinMap elt
206 IF_NCG(COMMA RegFinMap elt -> [Reg] -> RegFinMap elt)
210 lookupUFM :: IdFinMap elt -> Id -> Maybe elt,
211 TyVarFinMap elt -> TyVar -> Maybe elt,
212 NameFinMap elt -> Name -> Maybe elt
213 IF_NCG(COMMA RegFinMap elt -> Reg -> Maybe elt)
217 :: IdFinMap elt -> elt -> Id -> elt,
218 TyVarFinMap elt -> elt -> TyVar -> elt,
219 NameFinMap elt -> elt -> Name -> elt
220 IF_NCG(COMMA RegFinMap elt -> elt -> Reg -> elt)
223 #endif {- __GLASGOW_HASKELL__ -}
227 %************************************************************************
229 \subsection{Andy Gill's underlying @UniqFM@ machinery}
231 %************************************************************************
233 ``Uniq Finite maps'' are the heart and soul of the compiler's
234 lookup-tables/environments. Important stuff! It works well with
235 Dense and Sparse ranges.
236 Both @Uq@ Finite maps and @Hash@ Finite Maps
237 are built ontop of Int Finite Maps.
239 This code is explained in the paper:
241 A Gill, S Peyton Jones, B O'Sullivan, W Partain and Aqua Friends
242 "A Cheap balancing act that grows on a tree"
243 Glasgow FP Workshop, Sep 1994, pp??-??
246 %************************************************************************
248 \subsubsection{The @UniqFM@ type, and signatures for the functions}
250 %************************************************************************
252 @UniqFM a@ is a mapping from Unique to a.
254 First, the DataType itself; which is either a Node, a Leaf, or an Empty.
259 | LeafUFM FAST_INT ele
260 | NodeUFM FAST_INT -- the switching
261 FAST_INT -- the delta
265 class Uniquable a where
266 uniqueOf :: a -> Unique
268 -- for debugging only :-)
270 instance Text (UniqFM a) where
271 showsPrec _ (NodeUFM a b t1 t2) =
272 showString "NodeUFM " . shows (IBOX(a))
273 . showString " " . shows (IBOX(b))
274 . showString " (" . shows t1
275 . showString ") (" . shows t2
277 showsPrec _ (LeafUFM x a) = showString "LeafUFM " . shows (IBOX(x))
278 showsPrec _ (EmptyUFM) = id
282 %************************************************************************
284 \subsubsection{The @UniqFM@ functions}
286 %************************************************************************
288 First the ways of building a UniqFM.
292 unitUFM key elt = mkLeafUFM (u2i (uniqueOf key)) elt
293 unitDirectlyUFM key elt = mkLeafUFM (u2i key) elt
295 listToUFM key_elt_pairs
296 = addListToUFM_C use_snd EmptyUFM key_elt_pairs
298 listToUFM_Directly uniq_elt_pairs
299 = addListToUFM_directly_C use_snd EmptyUFM uniq_elt_pairs
302 Now ways of adding things to UniqFMs.
304 There is an alternative version of @addListToUFM_C@, that uses @plusUFM@,
305 but the semantics of this operation demands a linear insertion;
306 perhaps the version without the combinator function
307 could be optimised using it.
310 addToUFM fm key elt = addToUFM_C use_snd fm key elt
312 addToUFM_Directly fm u elt = insert_ele use_snd fm (u2i u) elt
314 addToUFM_C combiner fm key elt
315 = insert_ele combiner fm (u2i (uniqueOf key)) elt
317 addListToUFM fm key_elt_pairs = addListToUFM_C use_snd fm key_elt_pairs
318 addListToUFM_Directly fm uniq_elt_pairs = addListToUFM_directly_C use_snd fm uniq_elt_pairs
320 addListToUFM_C combiner fm key_elt_pairs
321 = foldl (\ fm (k, e) -> insert_ele combiner fm (u2i (uniqueOf k)) e)
324 addListToUFM_directly_C combiner fm uniq_elt_pairs
325 = foldl (\ fm (k, e) -> insert_ele combiner fm (u2i k) e)
329 Now ways of removing things from UniqFM.
332 delListFromUFM fm lst = foldl delFromUFM fm lst
334 delFromUFM fm key = delete fm (u2i (uniqueOf key))
336 delete EmptyUFM _ = EmptyUFM
337 delete fm key = del_ele fm
339 del_ele :: UniqFM a -> UniqFM a
341 del_ele lf@(LeafUFM j _)
342 | j _EQ_ key = EmptyUFM
343 | otherwise = lf -- no delete!
345 del_ele nd@(NodeUFM j p t1 t2)
347 = mkSLNodeUFM (NodeUFMData j p) (del_ele t1) t2
349 = mkLSNodeUFM (NodeUFMData j p) t1 (del_ele t2)
351 del_ele _ = panic "Found EmptyUFM FM when rec-deleting"
354 Now ways of adding two UniqFM's together.
357 plusUFM tr1 tr2 = plusUFM_C use_snd tr1 tr2
359 plusUFM_C f EmptyUFM tr = tr
360 plusUFM_C f tr EmptyUFM = tr
361 plusUFM_C f fm1 fm2 = mix_trees fm1 fm2
363 mix_trees (LeafUFM i a) t2 = insert_ele (flip f) t2 i a
364 mix_trees t1 (LeafUFM i a) = insert_ele f t1 i a
366 mix_trees left_t@(NodeUFM j p t1 t2) right_t@(NodeUFM j' p' t1' t2')
368 (ask_about_common_ancestor
372 -- Given a disjoint j,j' (p >^ p' && p' >^ p):
376 -- t1 t2 t1' t2' j j'
381 mix_branches (NewRoot nd False)
382 = mkLLNodeUFM nd left_t right_t
383 mix_branches (NewRoot nd True)
384 = mkLLNodeUFM nd right_t left_t
390 -- t1 t2 t1' t2' t1 + t1' t2 + t2'
392 mix_branches (SameRoot)
393 = mkSSNodeUFM (NodeUFMData j p)
396 -- Now the 4 different other ways; all like this:
398 -- Given j >^ j' (and, say, j > j')
402 -- t1 t2 t1' t2' t1 t2 + j'
405 mix_branches (LeftRoot Leftt) -- | trace "LL" True
408 (mix_trees t1 right_t)
411 mix_branches (LeftRoot Rightt) -- | trace "LR" True
415 (mix_trees t2 right_t)
417 mix_branches (RightRoot Leftt) -- | trace "RL" True
420 (mix_trees left_t t1')
423 mix_branches (RightRoot Rightt) -- | trace "RR" True
427 (mix_trees left_t t2')
429 mix_trees _ _ = panic "EmptyUFM found when inserting into plusInt"
432 And ways of subtracting them. First the base cases,
433 then the full D&C approach.
436 minusUFM EmptyUFM _ = EmptyUFM
437 minusUFM t1 EmptyUFM = t1
438 minusUFM fm1 fm2 = minus_trees fm1 fm2
441 -- Notice the asymetry of subtraction
443 minus_trees lf@(LeafUFM i a) t2 =
448 minus_trees t1 (LeafUFM i _) = delete t1 i
450 minus_trees left_t@(NodeUFM j p t1 t2) right_t@(NodeUFM j' p' t1' t2')
452 (ask_about_common_ancestor
456 -- Given a disjoint j,j' (p >^ p' && p' >^ p):
460 -- t1 t2 t1' t2' t1 t2
465 minus_branches (NewRoot nd _) = left_t
471 -- t1 t2 t1' t2' t1 + t1' t2 + t2'
473 minus_branches (SameRoot)
474 = mkSSNodeUFM (NodeUFMData j p)
477 -- Now the 4 different other ways; all like this:
478 -- again, with asymatry
481 -- The left is above the right
483 minus_branches (LeftRoot Leftt)
486 (minus_trees t1 right_t)
488 minus_branches (LeftRoot Rightt)
492 (minus_trees t2 right_t)
495 -- The right is above the left
497 minus_branches (RightRoot Leftt)
498 = minus_trees left_t t1'
499 minus_branches (RightRoot Rightt)
500 = minus_trees left_t t2'
502 minus_trees _ _ = panic "EmptyUFM found when insering into plusInt"
505 And taking the intersection of two UniqFM's.
508 intersectUFM t1 t2 = intersectUFM_C use_snd t1 t2
510 intersectUFM_C f EmptyUFM _ = EmptyUFM
511 intersectUFM_C f _ EmptyUFM = EmptyUFM
512 intersectUFM_C f fm1 fm2 = intersect_trees fm1 fm2
514 intersect_trees (LeafUFM i a) t2 =
517 Just b -> mkLeafUFM i (f a b)
519 intersect_trees t1 (LeafUFM i a) =
522 Just b -> mkLeafUFM i (f b a)
524 intersect_trees left_t@(NodeUFM j p t1 t2) right_t@(NodeUFM j' p' t1' t2')
526 (ask_about_common_ancestor
530 -- Given a disjoint j,j' (p >^ p' && p' >^ p):
533 -- / \ + / \ ==> EmptyUFM
538 intersect_branches (NewRoot nd _) = EmptyUFM
544 -- t1 t2 t1' t2' t1 x t1' t2 x t2'
546 intersect_branches (SameRoot)
547 = mkSSNodeUFM (NodeUFMData j p)
548 (intersect_trees t1 t1')
549 (intersect_trees t2 t2')
550 -- Now the 4 different other ways; all like this:
552 -- Given j >^ j' (and, say, j > j')
556 -- t1 t2 t1' t2' t1' t2'
558 -- This does cut down the search space quite a bit.
560 intersect_branches (LeftRoot Leftt)
561 = intersect_trees t1 right_t
562 intersect_branches (LeftRoot Rightt)
563 = intersect_trees t2 right_t
564 intersect_branches (RightRoot Leftt)
565 = intersect_trees left_t t1'
566 intersect_branches (RightRoot Rightt)
567 = intersect_trees left_t t2'
569 intersect_trees x y = panic ("EmptyUFM found when intersecting trees")
572 Now the usual set of `collection' operators, like map, fold, etc.
575 foldUFM fn a EmptyUFM = a
576 foldUFM fn a fm = fold_tree fn a fm
578 mapUFM fn EmptyUFM = EmptyUFM
579 mapUFM fn fm = map_tree fn fm
581 filterUFM fn EmptyUFM = EmptyUFM
582 filterUFM fn fm = filter_tree fn fm
585 Note, this takes a long time, O(n), but
586 because we dont want to do this very often, we put up with this.
587 O'rable, but how often do we look at the size of
592 sizeUFM (NodeUFM _ _ t1 t2) = sizeUFM t1 + sizeUFM t2
593 sizeUFM (LeafUFM _ _) = 1
595 isNullUFM EmptyUFM = True
599 looking up in a hurry is the {\em whole point} of this binary tree lark.
600 Lookup up a binary tree is easy (and fast).
603 lookupUFM fm key = lookup fm (u2i (uniqueOf key))
604 lookupUFM_Directly fm key = lookup fm (u2i key)
606 lookupWithDefaultUFM fm deflt key
607 = case lookup fm (u2i (uniqueOf key)) of
611 lookupWithDefaultUFM_Directly fm deflt key
612 = case lookup fm (u2i key) of
616 lookup EmptyUFM _ = Nothing
617 lookup fm i = lookup_tree fm
619 lookup_tree :: UniqFM a -> Maybe a
621 lookup_tree (LeafUFM j b)
623 | otherwise = Nothing
624 lookup_tree (NodeUFM j p t1 t2)
625 | j _GT_ i = lookup_tree t1
626 | otherwise = lookup_tree t2
628 lookup_tree EmptyUFM = panic "lookup Failed"
631 folds are *wonderful* things.
634 eltsUFM EmptyUFM = []
635 eltsUFM fm = fold_tree (:) [] fm
637 ufmToList EmptyUFM = []
639 = fold_tree (\ iu elt rest -> (mkUniqueGrimily iu, elt) : rest) [] fm
641 fold_tree f a (NodeUFM _ _ t1 t2) = fold_tree f (fold_tree f a t2) t1
642 fold_tree f a (LeafUFM iu obj) = f iu obj a
644 fold_tree f a EmptyUFM = panic "Should Never fold over an EmptyUFM"
647 %************************************************************************
649 \subsubsection{The @UniqFM@ type, and its functions}
651 %************************************************************************
653 You should always use these to build the tree.
654 There are 4 versions of mkNodeUFM, depending on
655 the strictness of the two sub-tree arguments.
656 The strictness is used *both* to prune out
657 empty trees, *and* to improve performance,
658 stoping needless thunks lying around.
659 The rule of thumb (from experence with these trees)
660 is make thunks strict, but data structures lazy.
661 If in doubt, use mkSSNodeUFM, which has the `strongest'
662 functionality, but may do a few needless evaluations.
665 mkLeafUFM :: FAST_INT -> a -> UniqFM a
666 mkLeafUFM i a = LeafUFM i a
668 -- The *ONLY* ways of building a NodeUFM.
670 mkSSNodeUFM (NodeUFMData j p) EmptyUFM t2 = t2
671 mkSSNodeUFM (NodeUFMData j p) t1 EmptyUFM = t1
672 mkSSNodeUFM (NodeUFMData j p) t1 t2
673 = ASSERT(correctNodeUFM (IBOX(j)) (IBOX(p)) t1 t2)
676 mkSLNodeUFM (NodeUFMData j p) EmptyUFM t2 = t2
677 mkSLNodeUFM (NodeUFMData j p) t1 t2
678 = ASSERT(correctNodeUFM (IBOX(j)) (IBOX(p)) t1 t2)
681 mkLSNodeUFM (NodeUFMData j p) t1 EmptyUFM = t1
682 mkLSNodeUFM (NodeUFMData j p) t1 t2
683 = ASSERT(correctNodeUFM (IBOX(j)) (IBOX(p)) t1 t2)
686 mkLLNodeUFM (NodeUFMData j p) t1 t2
687 = ASSERT(correctNodeUFM (IBOX(j)) (IBOX(p)) t1 t2)
697 correctNodeUFM j p t1 t2
698 = correct (j-p) (j-1) p t1 && correct j ((j-1)+p) p t2
700 correct low high _ (LeafUFM i _)
701 = low <= IBOX(i) && IBOX(i) <= high
702 correct low high above_p (NodeUFM j p _ _)
703 = low <= IBOX(j) && IBOX(j) <= high && above_p > IBOX(p)
704 correct _ _ _ EmptyUFM = panic "EmptyUFM stored inside a tree"
707 Note: doing SAT on this by hand seems to make it worse. Todo: Investigate,
708 and if necessary do $\lambda$ lifting on our functions that are bound.
718 insert_ele f EmptyUFM i new = mkLeafUFM i new
720 insert_ele f (LeafUFM j old) i new
722 mkLLNodeUFM (getCommonNodeUFMData
727 | j _EQ_ i = mkLeafUFM j (f old new)
729 mkLLNodeUFM (getCommonNodeUFMData
735 insert_ele f n@(NodeUFM j p t1 t2) i a
737 = if (i _GE_ (j _SUB_ p))
738 then mkSLNodeUFM (NodeUFMData j p) (insert_ele f t1 i a) t2
739 else mkLLNodeUFM (getCommonNodeUFMData
745 = if (i _LE_ ((j _SUB_ ILIT(1)) _ADD_ p))
746 then mkLSNodeUFM (NodeUFMData j p) t1 (insert_ele f t2 i a)
747 else mkLLNodeUFM (getCommonNodeUFMData
754 This has got a left to right ordering.
757 fold_tree f a (NodeUFM _ _ t1 t2) = fold_tree f (fold_tree f a t2) t1
758 fold_tree f a (LeafUFM _ obj) = f obj a
760 fold_tree f a EmptyUFM = panic "Should Never fold over an EmptyUFM"
764 map_tree f (NodeUFM j p t1 t2)
765 = mkSSNodeUFM (NodeUFMData j p) (map_tree f t1) (map_tree f t2)
766 map_tree f (LeafUFM i obj)
767 = mkLeafUFM i (f obj)
769 map_tree f _ = panic "map_tree failed"
773 filter_tree f nd@(NodeUFM j p t1 t2)
774 = mkSSNodeUFM (NodeUFMData j p) (filter_tree f t1) (filter_tree f t2)
776 filter_tree f lf@(LeafUFM i obj)
778 | otherwise = EmptyUFM
781 %************************************************************************
783 \subsubsection{The @UniqFM@ type, and signatures for the functions}
785 %************************************************************************
789 This is the information that is held inside a NodeUFM, packaged up for
794 = NodeUFMData FAST_INT
798 This is the information used when computing new NodeUFMs.
801 data Side = Leftt | Rightt -- NB: avoid 1.3 names "Left" and "Right"
803 = LeftRoot Side -- which side is the right down ?
804 | RightRoot Side -- which side is the left down ?
805 | SameRoot -- they are the same !
806 | NewRoot NodeUFMData -- here's the new, common, root
807 Bool -- do you need to swap left and right ?
810 This specifies the relationship between NodeUFMData and CalcNodeUFMData.
813 indexToRoot :: FAST_INT -> NodeUFMData
817 l = (ILIT(1) :: FAST_INT)
819 NodeUFMData (((i `shiftR_` l) `shiftL_` l) _ADD_ ILIT(1)) l
821 getCommonNodeUFMData :: NodeUFMData -> NodeUFMData -> NodeUFMData
823 getCommonNodeUFMData (NodeUFMData i p) (NodeUFMData i2 p2)
824 | p _EQ_ p2 = getCommonNodeUFMData_ p j j2
825 | p _LT_ p2 = getCommonNodeUFMData_ p2 (j _QUOT_ (p2 _QUOT_ p)) j2
826 | otherwise = getCommonNodeUFMData_ p j (j2 _QUOT_ (p _QUOT_ p2))
828 l = (ILIT(1) :: FAST_INT)
829 j = i _QUOT_ (p `shiftL_` l)
830 j2 = i2 _QUOT_ (p2 `shiftL_` l)
832 getCommonNodeUFMData_ :: FAST_INT -> FAST_INT -> FAST_INT -> NodeUFMData
834 getCommonNodeUFMData_ p j j_
836 = NodeUFMData (((j `shiftL_` l) _ADD_ l) _MUL_ p) p
838 = getCommonNodeUFMData_ (p `shiftL_` l) (j `shiftR_` l) (j_ `shiftR_` l)
840 ask_about_common_ancestor :: NodeUFMData -> NodeUFMData -> CommonRoot
842 ask_about_common_ancestor x@(NodeUFMData j p) y@(NodeUFMData j2 p2)
843 | j _EQ_ j2 = SameRoot
845 = case getCommonNodeUFMData x y of
846 nd@(NodeUFMData j3 p3)
847 | j3 _EQ_ j -> LeftRoot (decideSide (j _GT_ j2))
848 | j3 _EQ_ j2 -> RightRoot (decideSide (j _LT_ j2))
849 | otherwise -> NewRoot nd (j _GT_ j2)
851 decideSide :: Bool -> Side
852 decideSide True = Leftt
853 decideSide False = Rightt
856 This might be better in Util.lhs ?
859 Now the bit twiddling functions.
861 shiftL_ :: FAST_INT -> FAST_INT -> FAST_INT
862 shiftR_ :: FAST_INT -> FAST_INT -> FAST_INT
864 #if __GLASGOW_HASKELL__
865 {-# INLINE shiftL_ #-}
866 {-# INLINE shiftR_ #-}
867 shiftL_ n p = word2Int#((int2Word# n) `shiftL#` p)
868 shiftR_ n p = word2Int#((int2Word# n) `shiftr` p)
870 shiftr x y = shiftRA# x y
873 shiftL_ n p = n * (2 ^ p)
874 shiftR_ n p = n `quot` (2 ^ p)
879 Andy's extras: ToDo: to Util.
882 use_fst :: a -> b -> a
885 use_snd :: a -> b -> b