%
% (c) The University of Glasgow 2006
% (c) The AQUA Project, Glasgow University, 1994-1998
%

UniqFM: Specialised finite maps, for things with @Uniques@.

Basically, the things need to be in class @Uniquable@, and we use the
@getUnique@ method to grab their @Uniques@.

(A similar thing to @UniqSet@, as opposed to @Set@.)

The interface is based on @FiniteMap@s, but the implementation uses
@Data.IntMap@, which is both maitained and faster than the past
implementation (see commit log).

The @UniqFM@ interface maps directly to Data.IntMap, only
``Data.IntMap.union'' is left-biased and ``plusUFM'' right-biased
and ``addToUFM\_C'' and ``Data.IntMap.insertWith'' differ in the order
of arguments of combining function.

\begin{code}
{-# OPTIONS -Wall #-}
module UniqFM (
	-- * Unique-keyed mappings
	UniqFM,       -- abstract type

        -- ** Manipulating those mappings
	emptyUFM,
	unitUFM,
	unitDirectlyUFM,
	listToUFM,
	listToUFM_Directly,
	listToUFM_C,
	addToUFM,addToUFM_C,addToUFM_Acc,
	addListToUFM,addListToUFM_C,
	addToUFM_Directly,
	addListToUFM_Directly,
	delFromUFM,
	delFromUFM_Directly,
	delListFromUFM,
	plusUFM,
	plusUFM_C,
	minusUFM,
	intersectUFM,
	intersectUFM_C,
	foldUFM, foldUFM_Directly,
	mapUFM,
	elemUFM, elemUFM_Directly,
	filterUFM, filterUFM_Directly,
	sizeUFM,
	isNullUFM,
	lookupUFM, lookupUFM_Directly,
	lookupWithDefaultUFM, lookupWithDefaultUFM_Directly,
	eltsUFM, keysUFM, splitUFM,
	ufmToList 
    ) where

import Unique           ( Uniquable(..), Unique, getKey )
import Outputable

import qualified Data.IntMap as M
\end{code}

%************************************************************************
%*									*
\subsection{The signature of the module}
%*									*
%************************************************************************

\begin{code}
emptyUFM	:: UniqFM elt
isNullUFM	:: UniqFM elt -> Bool
unitUFM		:: Uniquable key => key -> elt -> UniqFM elt
unitDirectlyUFM -- got the Unique already
		:: Unique -> elt -> UniqFM elt
listToUFM	:: Uniquable key => [(key,elt)] -> UniqFM elt
listToUFM_Directly
		:: [(Unique, elt)] -> UniqFM elt
listToUFM_C     :: Uniquable key => (elt -> elt -> elt) 
                           -> [(key, elt)] 
                           -> UniqFM elt

addToUFM	:: Uniquable key => UniqFM elt -> key -> elt  -> UniqFM elt
addListToUFM	:: Uniquable key => UniqFM elt -> [(key,elt)] -> UniqFM elt
addListToUFM_Directly :: UniqFM elt -> [(Unique,elt)] -> UniqFM elt
addToUFM_Directly
		:: UniqFM elt -> Unique -> elt -> UniqFM elt

addToUFM_C	:: Uniquable key => (elt -> elt -> elt)	-- old -> new -> result
			   -> UniqFM elt 		-- old
			   -> key -> elt 		-- new
			   -> UniqFM elt		-- result

addToUFM_Acc	:: Uniquable key =>
			      (elt -> elts -> elts)	-- Add to existing
			   -> (elt -> elts)		-- New element
			   -> UniqFM elts 		-- old
			   -> key -> elt 		-- new
			   -> UniqFM elts		-- result

addListToUFM_C	:: Uniquable key => (elt -> elt -> elt)
			   -> UniqFM elt -> [(key,elt)]
			   -> UniqFM elt

delFromUFM	:: Uniquable key => UniqFM elt -> key	 -> UniqFM elt
delListFromUFM	:: Uniquable key => UniqFM elt -> [key] -> UniqFM elt
delFromUFM_Directly :: UniqFM elt -> Unique -> UniqFM elt

-- Bindings in right argument shadow those in the left
plusUFM		:: UniqFM elt -> UniqFM elt -> UniqFM elt

plusUFM_C	:: (elt -> elt -> elt)
		-> UniqFM elt -> UniqFM elt -> UniqFM elt

minusUFM	:: UniqFM elt1 -> UniqFM elt2 -> UniqFM elt1

intersectUFM	:: UniqFM elt -> UniqFM elt -> UniqFM elt
intersectUFM_C	:: (elt1 -> elt2 -> elt3)
		-> UniqFM elt1 -> UniqFM elt2 -> UniqFM elt3

foldUFM		:: (elt -> a -> a) -> a -> UniqFM elt -> a
foldUFM_Directly:: (Unique -> elt -> a -> a) -> a -> UniqFM elt -> a
mapUFM		:: (elt1 -> elt2) -> UniqFM elt1 -> UniqFM elt2
filterUFM	:: (elt -> Bool) -> UniqFM elt -> UniqFM elt
filterUFM_Directly :: (Unique -> elt -> Bool) -> UniqFM elt -> UniqFM elt

sizeUFM		:: UniqFM elt -> Int
--hashUFM		:: UniqFM elt -> Int
elemUFM		:: Uniquable key => key -> UniqFM elt -> Bool
elemUFM_Directly:: Unique -> UniqFM elt -> Bool

splitUFM        :: Uniquable key => UniqFM elt -> key -> (UniqFM elt, Maybe elt, UniqFM elt)
		   -- Splits a UFM into things less than, equal to, and greater than the key
lookupUFM	:: Uniquable key => UniqFM elt -> key -> Maybe elt
lookupUFM_Directly  -- when you've got the Unique already
		:: UniqFM elt -> Unique -> Maybe elt
lookupWithDefaultUFM
		:: Uniquable key => UniqFM elt -> elt -> key -> elt
lookupWithDefaultUFM_Directly
		:: UniqFM elt -> elt -> Unique -> elt
keysUFM		:: UniqFM elt -> [Unique]	-- Get the keys
eltsUFM		:: UniqFM elt -> [elt]
ufmToList	:: UniqFM elt -> [(Unique, elt)]

\end{code}

%************************************************************************
%*                                                                      *
\subsection{Implementation using ``Data.IntMap''}
%*                                                                      *
%************************************************************************

\begin{code}
newtype UniqFM ele = UFM (M.IntMap ele)

emptyUFM = UFM M.empty
isNullUFM (UFM m) = M.null m
unitUFM k v = UFM (M.singleton (getKey $ getUnique k) v)
unitDirectlyUFM u v = UFM (M.singleton (getKey u) v)
listToUFM = foldl (\m (k, v) -> addToUFM m k v) emptyUFM
listToUFM_Directly = foldl (\m (u, v) -> addToUFM_Directly m u v) emptyUFM
listToUFM_C f = foldl (\m (k, v) -> addToUFM_C f m k v) emptyUFM

addToUFM (UFM m) k v = UFM (M.insert (getKey $ getUnique k) v m)
addListToUFM = foldl (\m (k, v) -> addToUFM m k v)
addListToUFM_Directly = foldl (\m (k, v) -> addToUFM_Directly m k v)
addToUFM_Directly (UFM m) u v = UFM (M.insert (getKey u) v m)

-- Arguments of combining function of M.insertWith and addToUFM_C are flipped.
addToUFM_C f (UFM m) k v =
  UFM (M.insertWith (flip f) (getKey $ getUnique k) v m)
addToUFM_Acc exi new (UFM m) k v =
  UFM (M.insertWith (\_new old -> exi v old) (getKey $ getUnique k) (new v) m)
addListToUFM_C f = foldl (\m (k, v) -> addToUFM_C f m k v)

delFromUFM (UFM m) k = UFM (M.delete (getKey $ getUnique k) m)
delListFromUFM = foldl delFromUFM
delFromUFM_Directly (UFM m) u = UFM (M.delete (getKey u) m)

-- M.union is left-biased, plusUFM should be right-biased.
plusUFM (UFM x) (UFM y) = UFM (M.union y x)
plusUFM_C f (UFM x) (UFM y) = UFM (M.unionWith f x y)
minusUFM (UFM x) (UFM y) = UFM (M.difference x y)
intersectUFM (UFM x) (UFM y) = UFM (M.intersection x y)
#if __GLASGOW_HASKELL__ >= 611
intersectUFM_C f (UFM x) (UFM y) = UFM (M.intersectionWith f x y)
#else
-- In GHC 6.10, intersectionWith is (a -> b -> a) instead of (a -> b -> c),
-- so we need to jump through some hoops to get the more general type.
intersectUFM_C f (UFM x) (UFM y) = UFM z
    where z = let x' = M.map Left x
                  f' (Left a) b = Right (f a b)
                  f' (Right _) _ = panic "intersectUFM_C: f': Right"
                  z' = M.intersectionWith f' x' y
                  fromRight (Right a) = a
                  fromRight _ = panic "intersectUFM_C: Left"
              in M.map fromRight z'
#endif

foldUFM k z (UFM m) = M.fold k z m
foldUFM_Directly k z (UFM m) = M.foldWithKey (k . getUnique) z m
mapUFM f (UFM m) = UFM (M.map f m)
filterUFM p (UFM m) = UFM (M.filter p m)
filterUFM_Directly p (UFM m) = UFM (M.filterWithKey (p . getUnique) m)

sizeUFM (UFM m) = M.size m
elemUFM k (UFM m) = M.member (getKey $ getUnique k) m
elemUFM_Directly u (UFM m) = M.member (getKey u) m

splitUFM (UFM m) k = case M.splitLookup (getKey $ getUnique k) m of
                       (less, equal, greater) -> (UFM less, equal, UFM greater)
lookupUFM (UFM m) k = M.lookup (getKey $ getUnique k) m
lookupUFM_Directly (UFM m) u = M.lookup (getKey u) m
lookupWithDefaultUFM (UFM m) v k = M.findWithDefault v (getKey $ getUnique k) m
lookupWithDefaultUFM_Directly (UFM m) v u = M.findWithDefault v (getKey u) m
keysUFM (UFM m) = map getUnique $ M.keys m
eltsUFM (UFM m) = M.elems m
ufmToList (UFM m) = map (\(k, v) -> (getUnique k, v)) $ M.toList m

\end{code}

%************************************************************************
%*                                                                      *
\subsection{Output-ery}
%*                                                                      *
%************************************************************************

\begin{code}
instance Outputable a => Outputable (UniqFM a) where
    ppr ufm = ppr (ufmToList ufm)
\end{code}
