encoding/Data/CharMap.hs
Henning Guenther 6101ee16ae Switch from Template-based code generating to text-based
Ignore-this: f58ceb5e1068be132b0a67a851b096f4
This has two advantages:
1. TemplateHaskell is painfully slow. There, I said it.
2. TemplateHaskell doesn't yet support some extensions that can be usefull for this library. Specifically the MagicHash extension.

darcs-hash:20090813023321-a4fee-0da13d0da6454f6ba3bd111ed6b80268d9e1b45c
2009-08-12 19:33:21 -07:00

73 lines
2.7 KiB
Haskell

module Data.CharMap where
import Data.Map.Static
import Data.Encoding.ByteSink
import Data.Encoding.Exception
import Control.Throws
import Data.Word
import Data.Char
import Prelude hiding (lookup)
data CharMap
= Node !Char !CharMap !CharMap
| DeadEnd
| LeafRange1 !Int !Word8
| LeafRange2 !Int !Word8 !Word8 !Word8
| LeafRange3 !Int !Word8 !Word8 !Word8 !Word8 !Word8
| LeafRange4 !Int !Word8 !Word8 !Word8 !Word8 !Word8 !Word8 !Word8
| LeafMap1 (StaticMap Char Word8)
| LeafMap2 (StaticMap Char Word16)
| LeafMap4 (StaticMap Char Word32)
mapEncode :: ByteSink m => Char -> CharMap -> m ()
mapEncode ch (Node rch l r)
| ch < rch = mapEncode ch l
| otherwise = mapEncode ch r
mapEncode ch DeadEnd = throwException (HasNoRepresentation ch)
mapEncode ch (LeafRange1 bch st)
= pushWord8 $ st + (fromIntegral ((ord ch) - bch))
mapEncode ch (LeafRange2 bch min1 min2 r2)
= let v = (ord ch) - bch
(w1,w2) = v `divMod` (fromIntegral r2)
in do
pushWord8 (fromIntegral w1 + min1)
pushWord8 (fromIntegral w2 + min2)
mapEncode ch (LeafRange3 bch min1 min2 r2 min3 r3)
= let v = (ord ch) - bch
(v1,w3) = v `divMod` (fromIntegral r3)
(w1,w2) = v1 `divMod` (fromIntegral r2)
in do
pushWord8 (fromIntegral w1 + min1)
pushWord8 (fromIntegral w2 + min2)
pushWord8 (fromIntegral w3 + min3)
mapEncode ch (LeafRange4 bch min1 min2 r2 min3 r3 min4 r4)
= let v = (ord ch) - bch
(v1,w4) = v `divMod` (fromIntegral r4)
(v2,w3) = v1 `divMod` (fromIntegral r3)
(w1,w2) = v2 `divMod` (fromIntegral r2)
in do
pushWord8 (fromIntegral w1 + min1)
pushWord8 (fromIntegral w2 + min2)
pushWord8 (fromIntegral w3 + min3)
pushWord8 (fromIntegral w4 + min4)
mapEncode ch (LeafMap1 mp) = case lookup ch mp of
Nothing -> throwException (HasNoRepresentation ch)
Just v -> pushWord8 v
mapEncode ch (LeafMap2 mp) = case lookup ch mp of
Nothing -> throwException (HasNoRepresentation ch)
Just v -> pushWord16be v
mapEncode ch (LeafMap4 mp) = case lookup ch mp of
Nothing -> throwException (HasNoRepresentation ch)
Just v -> pushWord32be v
mapMember :: Char -> CharMap -> Bool
mapMember c (Node rc l r)
| c < rc = mapMember c l
| otherwise = mapMember c r
mapMember c DeadEnd = False
mapMember c (LeafMap1 mp) = member c mp
mapMember c (LeafMap2 mp) = member c mp
mapMember c (LeafMap4 mp) = member c mp
mapMember c _ = True