-- | Put bits easily.

module Data.Binary.Bits.Put
          ( BitPut
          , runBitPut
          , joinPut

          -- * Data types
          -- ** Bool
          , putBool

          -- ** Words
          , putWord8
          , putWord16be
          , putWord32be
          , putWord64be

          -- ** ByteString
          , putByteString
          )
          where

import Data.Bits ((.&.), (.|.))

import qualified Data.Binary.Builder as B
import qualified Data.Binary.Put as Put
import qualified Data.Bits as Bits
import qualified Data.ByteString as ByteString
import qualified Data.Word as Word

data BitPut a = BitPut { BitPut a -> S -> PairS a
run :: (S -> PairS a) }

data PairS a = PairS a {-# UNPACK #-} !S

data S = S !B.Builder !Word.Word8 !Int

-- | Put a 1 bit 'Bool'.
putBool :: Bool -> BitPut ()
putBool :: Bool -> BitPut ()
putBool Bool
b = Int -> Word8 -> BitPut ()
putWord8 Int
1 (if Bool
b then Word8
0xff else Word8
0x00)

-- | make_mask 3 = 00000111
make_mask :: (Bits.Bits a, Num a) => Int -> a
make_mask :: Int -> a
make_mask Int
n = (a
1 a -> Int -> a
forall a. Bits a => a -> Int -> a
`Bits.shiftL` Int -> Int
forall a b. (Integral a, Num b) => a -> b
fromIntegral Int
n) a -> a -> a
forall a. Num a => a -> a -> a
- a
1
{-# SPECIALIZE make_mask :: Int -> Int #-}
{-# SPECIALIZE make_mask :: Int -> Word #-}
{-# SPECIALIZE make_mask :: Int -> Word.Word8 #-}
{-# SPECIALIZE make_mask :: Int -> Word.Word16 #-}
{-# SPECIALIZE make_mask :: Int -> Word.Word32 #-}
{-# SPECIALIZE make_mask :: Int -> Word.Word64 #-}

-- | Put the @n@ lower bits of a 'Word8'.
putWord8 :: Int -> Word.Word8 -> BitPut ()
putWord8 :: Int -> Word8 -> BitPut ()
putWord8 Int
n Word8
w = (S -> PairS ()) -> BitPut ()
forall a. (S -> PairS a) -> BitPut a
BitPut ((S -> PairS ()) -> BitPut ()) -> (S -> PairS ()) -> BitPut ()
forall a b. (a -> b) -> a -> b
$ \S
s -> () -> S -> PairS ()
forall a. a -> S -> PairS a
PairS () (S -> PairS ()) -> S -> PairS ()
forall a b. (a -> b) -> a -> b
$
  let w' :: Word8
w' = Int -> Word8
forall a. (Bits a, Num a) => Int -> a
make_mask Int
n Word8 -> Word8 -> Word8
forall a. Bits a => a -> a -> a
.&. Word8
w in
  case S
s of
                -- a whole word8, no offset
    (S Builder
b Word8
t Int
o) | Int
n Int -> Int -> Bool
forall a. Eq a => a -> a -> Bool
== Int
8 Bool -> Bool -> Bool
&& Int
o Int -> Int -> Bool
forall a. Eq a => a -> a -> Bool
== Int
0 -> S -> S
flush (S -> S) -> S -> S
forall a b. (a -> b) -> a -> b
$ Builder -> Word8 -> Int -> S
S Builder
b Word8
w Int
n
                -- less than a word8, will fit in the current word8
              | Int
n Int -> Int -> Bool
forall a. Ord a => a -> a -> Bool
<= Int
8 Int -> Int -> Int
forall a. Num a => a -> a -> a
- Int
o       -> S -> S
flush (S -> S) -> S -> S
forall a b. (a -> b) -> a -> b
$ Builder -> Word8 -> Int -> S
S Builder
b (Word8
t Word8 -> Word8 -> Word8
forall a. Bits a => a -> a -> a
.|. (Word8
w' Word8 -> Int -> Word8
forall a. Bits a => a -> Int -> a
`Bits.shiftL` (Int
8 Int -> Int -> Int
forall a. Num a => a -> a -> a
- Int
n Int -> Int -> Int
forall a. Num a => a -> a -> a
- Int
o))) (Int
oInt -> Int -> Int
forall a. Num a => a -> a -> a
+Int
n)
                -- will finish this word8, and spill into the next one
              | Bool
otherwise -> S -> S
flush (S -> S) -> S -> S
forall a b. (a -> b) -> a -> b
$
                              let o' :: Int
o' = Int
o Int -> Int -> Int
forall a. Num a => a -> a -> a
+ Int
n Int -> Int -> Int
forall a. Num a => a -> a -> a
- Int
8
                                  b' :: Word8
b' = Word8
t Word8 -> Word8 -> Word8
forall a. Bits a => a -> a -> a
.|. (Word8
w' Word8 -> Int -> Word8
forall a. Bits a => a -> Int -> a
`Bits.shiftR` Int
o')
                                  t' :: Word8
t' = Word8
w Word8 -> Int -> Word8
forall a. Bits a => a -> Int -> a
`Bits.shiftL` (Int
8 Int -> Int -> Int
forall a. Num a => a -> a -> a
- Int
o')
                              in Builder -> Word8 -> Int -> S
S (Builder
b Builder -> Builder -> Builder
forall a. Monoid a => a -> a -> a
`mappend` Word8 -> Builder
B.singleton Word8
b') Word8
t' Int
o'

-- | Put the @n@ lower bits of a 'Word16'.
putWord16be :: Int -> Word.Word16 -> BitPut ()
putWord16be :: Int -> Word16 -> BitPut ()
putWord16be Int
n Word16
w
  | Int
n Int -> Int -> Bool
forall a. Ord a => a -> a -> Bool
<= Int
8 = Int -> Word8 -> BitPut ()
putWord8 Int
n (Word16 -> Word8
forall a b. (Integral a, Num b) => a -> b
fromIntegral Word16
w)
  | Bool
otherwise =
      (S -> PairS ()) -> BitPut ()
forall a. (S -> PairS a) -> BitPut a
BitPut ((S -> PairS ()) -> BitPut ()) -> (S -> PairS ()) -> BitPut ()
forall a b. (a -> b) -> a -> b
$ \S
s -> () -> S -> PairS ()
forall a. a -> S -> PairS a
PairS () (S -> PairS ()) -> S -> PairS ()
forall a b. (a -> b) -> a -> b
$
        let w' :: Word16
w' = Int -> Word16
forall a. (Bits a, Num a) => Int -> a
make_mask Int
n Word16 -> Word16 -> Word16
forall a. Bits a => a -> a -> a
.&. Word16
w in
        case S
s of
          -- as n>=9, it's too big to fit into one single byte
          -- it'll either use 2 or 3 bytes
                                     -- it'll fit in 2 bytes
          (S Builder
b Word8
t Int
o) | Int
o Int -> Int -> Int
forall a. Num a => a -> a -> a
+ Int
n Int -> Int -> Bool
forall a. Ord a => a -> a -> Bool
<= Int
16 -> S -> S
flush (S -> S) -> S -> S
forall a b. (a -> b) -> a -> b
$
                        let o' :: Int
o' = Int
o Int -> Int -> Int
forall a. Num a => a -> a -> a
+ Int
n Int -> Int -> Int
forall a. Num a => a -> a -> a
- Int
8
                            b' :: Word8
b' = Word8
t Word8 -> Word8 -> Word8
forall a. Bits a => a -> a -> a
.|. Word16 -> Word8
forall a b. (Integral a, Num b) => a -> b
fromIntegral (Word16
w' Word16 -> Int -> Word16
forall a. Bits a => a -> Int -> a
`Bits.shiftR` Int
o')
                            t' :: Word8
t' = Word16 -> Word8
forall a b. (Integral a, Num b) => a -> b
fromIntegral (Word16
w Word16 -> Int -> Word16
forall a. Bits a => a -> Int -> a
`Bits.shiftL` (Int
8Int -> Int -> Int
forall a. Num a => a -> a -> a
-Int
o'))
                        in (Builder -> Word8 -> Int -> S
S (Builder
b Builder -> Builder -> Builder
forall a. Monoid a => a -> a -> a
`mappend` Word8 -> Builder
B.singleton Word8
b') Word8
t' Int
o')
                                   -- 3 bytes required
                    | Bool
otherwise -> S -> S
flush (S -> S) -> S -> S
forall a b. (a -> b) -> a -> b
$
                        let o' :: Int
o'  = Int
o Int -> Int -> Int
forall a. Num a => a -> a -> a
+ Int
n Int -> Int -> Int
forall a. Num a => a -> a -> a
- Int
16
                            b' :: Word8
b'  = Word8
t Word8 -> Word8 -> Word8
forall a. Bits a => a -> a -> a
.|. Word16 -> Word8
forall a b. (Integral a, Num b) => a -> b
fromIntegral (Word16
w' Word16 -> Int -> Word16
forall a. Bits a => a -> Int -> a
`Bits.shiftR` (Int
o' Int -> Int -> Int
forall a. Num a => a -> a -> a
+ Int
8))
                            b'' :: Word8
b'' = Word16 -> Word8
forall a b. (Integral a, Num b) => a -> b
fromIntegral ((Word16
w Word16 -> Int -> Word16
forall a. Bits a => a -> Int -> a
`Bits.shiftR` Int
o') Word16 -> Word16 -> Word16
forall a. Bits a => a -> a -> a
.&. Word16
0xff)
                            t' :: Word8
t'  = Word16 -> Word8
forall a b. (Integral a, Num b) => a -> b
fromIntegral (Word16
w Word16 -> Int -> Word16
forall a. Bits a => a -> Int -> a
`Bits.shiftL` (Int
8Int -> Int -> Int
forall a. Num a => a -> a -> a
-Int
o'))
                        in (Builder -> Word8 -> Int -> S
S (Builder
b Builder -> Builder -> Builder
forall a. Monoid a => a -> a -> a
`mappend` Word8 -> Builder
B.singleton Word8
b' Builder -> Builder -> Builder
forall a. Monoid a => a -> a -> a
`mappend` Word8 -> Builder
B.singleton Word8
b'') Word8
t' Int
o')

-- | Put the @n@ lower bits of a 'Word32'.
putWord32be :: Int -> Word.Word32 -> BitPut ()
putWord32be :: Int -> Word32 -> BitPut ()
putWord32be Int
n Word32
w
  | Int
n Int -> Int -> Bool
forall a. Ord a => a -> a -> Bool
<= Int
16 = Int -> Word16 -> BitPut ()
putWord16be Int
n (Word32 -> Word16
forall a b. (Integral a, Num b) => a -> b
fromIntegral Word32
w)
  | Bool
otherwise = do
      Int -> Word32 -> BitPut ()
putWord32be (Int
nInt -> Int -> Int
forall a. Num a => a -> a -> a
-Int
16) (Word32
wWord32 -> Int -> Word32
forall a. Bits a => a -> Int -> a
`Bits.shiftR`Int
16)
      Int -> Word32 -> BitPut ()
putWord32be    Int
16  (Word32
w Word32 -> Word32 -> Word32
forall a. Bits a => a -> a -> a
.&. Word32
0x0000ffff)

-- | Put the @n@ lower bits of a 'Word64'.
putWord64be :: Int -> Word.Word64 -> BitPut ()
putWord64be :: Int -> Word64 -> BitPut ()
putWord64be Int
n Word64
w
  | Int
n Int -> Int -> Bool
forall a. Ord a => a -> a -> Bool
<= Int
32 = Int -> Word32 -> BitPut ()
putWord32be Int
n (Word64 -> Word32
forall a b. (Integral a, Num b) => a -> b
fromIntegral Word64
w)
  | Bool
otherwise = do
      Int -> Word64 -> BitPut ()
putWord64be (Int
nInt -> Int -> Int
forall a. Num a => a -> a -> a
-Int
32) (Word64
wWord64 -> Int -> Word64
forall a. Bits a => a -> Int -> a
`Bits.shiftR`Int
32)
      Int -> Word64 -> BitPut ()
putWord64be    Int
32  (Word64
w Word64 -> Word64 -> Word64
forall a. Bits a => a -> a -> a
.&. Word64
0xffffffff)

-- | Put a 'ByteString'.
putByteString :: ByteString.ByteString -> BitPut ()
putByteString :: ByteString -> BitPut ()
putByteString ByteString
bs = do
  Bool
offset <- BitPut Bool
hasOffset
  if Bool
offset
    then (Word8 -> BitPut ()) -> [Word8] -> BitPut ()
forall (t :: * -> *) (m :: * -> *) a b.
(Foldable t, Monad m) =>
(a -> m b) -> t a -> m ()
mapM_ (Int -> Word8 -> BitPut ()
putWord8 Int
8) (ByteString -> [Word8]
ByteString.unpack ByteString
bs) -- naive
    else Put -> BitPut ()
joinPut (ByteString -> Put
Put.putByteString ByteString
bs)
  where
    hasOffset :: BitPut Bool
hasOffset = (S -> PairS Bool) -> BitPut Bool
forall a. (S -> PairS a) -> BitPut a
BitPut ((S -> PairS Bool) -> BitPut Bool)
-> (S -> PairS Bool) -> BitPut Bool
forall a b. (a -> b) -> a -> b
$ \ s :: S
s@(S Builder
_ Word8
_ Int
o) -> Bool -> S -> PairS Bool
forall a. a -> S -> PairS a
PairS (Int
o Int -> Int -> Bool
forall a. Eq a => a -> a -> Bool
/= Int
0) S
s

-- | Run a 'Put' inside 'BitPut'. Any partially written bytes will be flushed
-- before 'Put' executes to ensure byte alignment.
joinPut :: Put.Put -> BitPut ()
joinPut :: Put -> BitPut ()
joinPut Put
m = (S -> PairS ()) -> BitPut ()
forall a. (S -> PairS a) -> BitPut a
BitPut ((S -> PairS ()) -> BitPut ()) -> (S -> PairS ()) -> BitPut ()
forall a b. (a -> b) -> a -> b
$ \S
s0 -> () -> S -> PairS ()
forall a. a -> S -> PairS a
PairS () (S -> PairS ()) -> S -> PairS ()
forall a b. (a -> b) -> a -> b
$
  let (S Builder
b0 Word8
_ Int
_) = S -> S
flushIncomplete S
s0
      b :: Builder
b = Put -> Builder
forall a. PutM a -> Builder
Put.execPut Put
m
  in (Builder -> Word8 -> Int -> S
S (Builder
b0Builder -> Builder -> Builder
forall a. Monoid a => a -> a -> a
`mappend`Builder
b) Word8
0 Int
0)

flush :: S -> S
flush :: S -> S
flush s :: S
s@(S Builder
b Word8
w Int
o)
  | Int
o Int -> Int -> Bool
forall a. Ord a => a -> a -> Bool
> Int
8 = [Char] -> S
forall a. HasCallStack => [Char] -> a
error [Char]
"flush: offset > 8"
  | Int
o Int -> Int -> Bool
forall a. Eq a => a -> a -> Bool
== Int
8 = Builder -> Word8 -> Int -> S
S (Builder
b Builder -> Builder -> Builder
forall a. Monoid a => a -> a -> a
`mappend` Word8 -> Builder
B.singleton Word8
w) Word8
0 Int
0
  | Bool
otherwise = S
s

flushIncomplete :: S -> S
flushIncomplete :: S -> S
flushIncomplete s :: S
s@(S Builder
b Word8
w Int
o)
  | Int
o Int -> Int -> Bool
forall a. Eq a => a -> a -> Bool
== Int
0 = S
s
  | Bool
otherwise = (Builder -> Word8 -> Int -> S
S (Builder
b Builder -> Builder -> Builder
forall a. Monoid a => a -> a -> a
`mappend` Word8 -> Builder
B.singleton Word8
w) Word8
0 Int
0)

-- | Run the 'BitPut' monad inside 'Put'.
runBitPut :: BitPut () -> Put.Put
runBitPut :: BitPut () -> Put
runBitPut BitPut ()
m = Builder -> Put
Put.putBuilder Builder
b
  where
  PairS ()
_ S
s = BitPut () -> S -> PairS ()
forall a. BitPut a -> S -> PairS a
run BitPut ()
m (Builder -> Word8 -> Int -> S
S Builder
forall a. Monoid a => a
mempty Word8
0 Int
0)
  (S Builder
b Word8
_ Int
_) = S -> S
flushIncomplete S
s

instance Functor BitPut where
  fmap :: (a -> b) -> BitPut a -> BitPut b
fmap a -> b
f (BitPut S -> PairS a
k) = (S -> PairS b) -> BitPut b
forall a. (S -> PairS a) -> BitPut a
BitPut ((S -> PairS b) -> BitPut b) -> (S -> PairS b) -> BitPut b
forall a b. (a -> b) -> a -> b
$ \S
s ->
    let PairS a
x S
s' = S -> PairS a
k S
s
    in b -> S -> PairS b
forall a. a -> S -> PairS a
PairS (a -> b
f a
x) S
s'

instance Applicative BitPut where
  pure :: a -> BitPut a
pure a
a = (S -> PairS a) -> BitPut a
forall a. (S -> PairS a) -> BitPut a
BitPut (\S
s -> a -> S -> PairS a
forall a. a -> S -> PairS a
PairS a
a S
s)
  (BitPut S -> PairS (a -> b)
f) <*> :: BitPut (a -> b) -> BitPut a -> BitPut b
<*> (BitPut S -> PairS a
g) = (S -> PairS b) -> BitPut b
forall a. (S -> PairS a) -> BitPut a
BitPut ((S -> PairS b) -> BitPut b) -> (S -> PairS b) -> BitPut b
forall a b. (a -> b) -> a -> b
$ \S
s ->
    let PairS a -> b
a S
s' = S -> PairS (a -> b)
f S
s
        PairS a
b S
s'' = S -> PairS a
g S
s'
    in b -> S -> PairS b
forall a. a -> S -> PairS a
PairS (a -> b
a a
b) S
s''

instance Monad BitPut where
  BitPut a
m >>= :: BitPut a -> (a -> BitPut b) -> BitPut b
>>= a -> BitPut b
k = (S -> PairS b) -> BitPut b
forall a. (S -> PairS a) -> BitPut a
BitPut ((S -> PairS b) -> BitPut b) -> (S -> PairS b) -> BitPut b
forall a b. (a -> b) -> a -> b
$ \S
s ->
    let PairS a
a S
s'  = BitPut a -> S -> PairS a
forall a. BitPut a -> S -> PairS a
run BitPut a
m S
s
        PairS b
b S
s'' = BitPut b -> S -> PairS b
forall a. BitPut a -> S -> PairS a
run (a -> BitPut b
k a
a) S
s'
    in b -> S -> PairS b
forall a. a -> S -> PairS a
PairS b
b S
s''
  return :: a -> BitPut a
return a
x = (S -> PairS a) -> BitPut a
forall a. (S -> PairS a) -> BitPut a
BitPut ((S -> PairS a) -> BitPut a) -> (S -> PairS a) -> BitPut a
forall a b. (a -> b) -> a -> b
$ \S
s -> a -> S -> PairS a
forall a. a -> S -> PairS a
PairS a
x S
s