module Satchmo.Binary.Data
( Number, bits, make
, width, number, constant, constantWidth
, fromBinary, toBinary, toBinaryWidth
)
where
import Prelude hiding ( and, or, not )
import qualified Satchmo.Code as C
import Satchmo.Boolean hiding ( constant )
import qualified Satchmo.Boolean as B
import Satchmo.Counting
data Number = Number
{ bits :: [ Boolean ]
}
instance C.Decode m Boolean Bool => C.Decode m Number Integer where
decode n = do ys <- mapM C.decode (bits n) ; return $ fromBinary ys
width :: Number -> Int
width n = length $ bits n
number :: MonadSAT m => Int -> m Number
number w = do
xs <- sequence $ replicate w boolean
return $ make xs
make :: [ Boolean ] -> Number
make xs = Number
{ bits = xs
}
fromBinary :: [ Bool ] -> Integer
fromBinary xs = foldr ( \ x y -> 2*y + if x then 1 else 0 ) 0 xs
toBinary :: Integer -> [ Bool ]
toBinary 0 = []
toBinary n =
let (d,m) = divMod n 2
in toEnum ( fromIntegral m ) : toBinary d
toBinaryWidth :: Int -> Integer -> [Bool]
toBinaryWidth width n =
let bs = toBinary n
leadingZeros = max 0 $ width (length bs)
in
bs ++ (replicate leadingZeros False)
constant :: MonadSAT m => Integer -> m Number
constant n = do
xs <- mapM B.constant $ toBinary n
return $ make xs
constantWidth :: MonadSAT m => Int -> Integer -> m Number
constantWidth width n = do
xs <- mapM B.constant $ toBinaryWidth width n
return $ make xs