@@ -4,6 +4,7 @@
44-- |
55-- Module : Data.Binary.Bits.Get
66-- Copyright : (c) Lennart Kolmodin 2010-2011
7+-- (c) Sylvain Henry 2015
78-- License : BSD3-style (see LICENSE)
89--
910-- Maintainer : kolmodin@gmail.com
@@ -59,11 +60,19 @@ module Data.Binary.Bits.Get
5960
6061 -- ** Get bytes
6162 , getBool
63+ , getBool#
6264 , getWord8
65+ , getWord16
66+ , getWord32
67+ , getWord64
6368 , getWord16be
6469 , getWord32be
6570 , getWord64be
6671
72+ -- ** Skip bits
73+ , skipBits
74+ , alignByte
75+
6776 -- * Blocks
6877
6978 -- $blocks
@@ -73,31 +82,41 @@ module Data.Binary.Bits.Get
7382 -- ** Read in Blocks
7483 , bool
7584 , word8
85+ , word16
86+ , word32
87+ , word64
7688 , word16be
7789 , word32be
7890 , word64be
7991 , byteString
8092 , Data.Binary.Bits.Get.getByteString
93+ , Data.Binary.Bits.Get.getLazyByteString
94+ , Data.Binary.Bits.Get.isEmpty
8195
8296 ) where
8397
84−import Data.Binary.Get as B ( runGet, Get, getByteString )
98+import Data.Binary.Get as B ( Get, getLazyByteString, isEmpty )
99+import Data.Binary.Get.Internal as B ( get, put, ensureN )
100+import Data.Binary.Bits.BitOrder
101+import Data.Binary.Bits.Internal
102+import Data.Binary.Bits.Alignment
85103
86104import Data.ByteString as B
105+import qualified Data.ByteString.Lazy as L
87106import Data.ByteString.Unsafe
107+import Foreign.Marshal.Alloc (mallocBytes)
108+import Foreign.Ptr
109+import Foreign.Storable (poke)
110+import System.IO.Unsafe (unsafePerformIO)
88111
89112import Data.Bits
90113import Data.Word
91−
92114import Control.Applicative
115+import Control.Monad (when,foldM_)
93116
94117import Prelude as P
95−
96−#if defined(__GLASGOW_HASKELL__) && !defined(__HADDOCK__)
97−import GHC.Base
98118import GHC.Word
99−#endif
100−
119+import GHC.Base (uncheckedShiftLWord8#, wordToWord8#, Int (..), andWord8#, Word8#, (-#), Int#, xorI#, eqWord8#, TYPE)
101120
102121-- $bitget
103122-- Parse bits using a monad.
@@ -145,188 +164,121 @@ import GHC.Word
145164--ipv6Header = 'runBitGet' ('block' ipv6headerblock)
146165-- @
147166
148−data S = S !ByteString -- Input
149− !Int -- Bit offset (0-7)
167+data S = S {-# UNPACK #-} !ByteString -- Input
168+ {-# UNPACK #-} !Int -- Bit offset (0-7)
169+ !BitOrder -- Bit order
150170 deriving (Show)
151171
152−-- | A block that will be read with only one boundry check. Needs to know the
153−-- number of bits in advance.
154−data Block a = Block !Int (S -> a)
155−
156−instance Functor Block where
157− fmap f (Block i p) = Block i (\s -> f (p s))
158−
159−instance Applicative Block where
160− pure a = Block 0 (\_ -> a)
161− (Block i p) <*> (Block j q) = Block (i+j) (\s -> p s $ q (incS i s))
162− (Block i _) *> (Block j q) = Block (i+j) (q . incS i)
163− (Block i p) <* (Block j _) = Block (i+j) p
164−
165−-- | Get a block. Will be read with one single boundry check, and
166−-- therefore requires a statically known number of bits.
167−-- Build blocks using 'bool', 'word8', 'word16be', 'word32be', 'word64be',
168−-- 'byteString' and 'Applicative'.
169−block :: Block a -> BitGet a
170−block (Block i p) = do
171− ensureBits i
172− modifyState (\s -> (incS i s, p s))
173−
174−
172+-- | Increment the current bit offset
175173incS :: Int -> S -> S
176−incS o (S bs n) =
177− let !o' = (n+o)
178− !d = o' `shiftR` 3
179− !n' = o' .&. make_mask 3
180− in S (unsafeDrop d bs) n'
181−
182−-- | make_mask 3 = 00000111
183−make_mask :: Bits a => Int -> a
184−make_mask n = (1 `shiftL` fromIntegral n) - 1
185−{-# SPECIALIZE make_mask :: Int -> Int #-}
186−{-# SPECIALIZE make_mask :: Int -> Word #-}
187−{-# SPECIALIZE make_mask :: Int -> Word8 #-}
188−{-# SPECIALIZE make_mask :: Int -> Word16 #-}
189−{-# SPECIALIZE make_mask :: Int -> Word32 #-}
190−{-# SPECIALIZE make_mask :: Int -> Word64 #-}
191−
192−bit_offset :: Int -> Int
193−bit_offset n = make_mask 3 .&. n
194−
195−byte_offset :: Int -> Int
196−byte_offset n = n `shiftR` 3
174+incS o (S bs n bo) = S (unsafeDrop d bs) n' bo
175+ where
176+ !o' = (n+o)
177+ !d = byte_offset o'
178+ !n' = bit_offset o'
197179
180+-- | Read a single bit
198181readBool :: S -> Bool
199−readBool (S bs n) = testBit (unsafeHead bs) (7-n)
200−
201−readWord8 :: Int -> S -> Word8
202−readWord8 n (S bs o)
203− -- no bits at all, return 0
204− | n == 0 = 0
205−
206− -- all bits are in the same byte
207− -- we just need to shift and mask them right
208− | n <= 8 - o = let w = unsafeHead bs
209− m = make_mask n
210− w' = (w `shiftr_w8` (8 - o - n)) .&. m
211− in w'
212−
213− -- the bits are in two different bytes
214− -- make a word16 using both bytes, and then shift and mask
215− | n <= 8 = let w = (fromIntegral (unsafeHead bs) `shiftl_w16` 8) .|.
216− (fromIntegral (unsafeIndex bs 1))
217− m = make_mask n
218− w' = (w `shiftr_w16` (16 - o - n)) .&. m
219− in fromIntegral w'
220−
221−
222−readWord16be :: Int -> S -> Word16
223−readWord16be n s@(S bs o)
224−
225− -- 8 or fewer bits, use readWord8
226− | n <= 8 = fromIntegral (readWord8 n s)
227−
228− -- handle 9 or more bits, stored in two bytes
229−
230− -- no offset, plain and simple 16 bytes
231− | o == 0 && n == 16 = let msb = fromIntegral (unsafeHead bs)
232− lsb = fromIntegral (unsafeIndex bs 1)
233− w = (msb `shiftl_w16` 8) .|. lsb
234− in w
235−
236− -- no offset, but not full 16 bytes
237− | o == 0 = let msb = fromIntegral (unsafeHead bs)
238− lsb = fromIntegral (unsafeIndex bs 1)
239− w = (msb `shiftl_w16` (n-8)) .|. (lsb `shiftr_w16` (16-n))
240− in w
241−
242− -- with offset, and n=9-16
243− | n <= 16 = readWithOffset s shiftl_w16 shiftr_w16 n
244−
245− | otherwise = error "readWord16be: tried to read more than 16 bits"
246−
247−readWord32be :: Int -> S -> Word32
248−readWord32be n s@(S _ o)
249− -- 8 or fewer bits, use readWord8
250− | n <= 8 = fromIntegral (readWord8 n s)
251−
252− -- 16 or fewer bits, use readWord16be
253− | n <= 16 = fromIntegral (readWord16be n s)
254−
255− | o == 0 = readWithoutOffset s shiftl_w32 shiftr_w32 n
256−
257− | n <= 32 = readWithOffset s shiftl_w32 shiftr_w32 n
258−
259− | otherwise = error "readWord32be: tried to read more than 32 bits"
260−
261−
262−readWord64be :: Int -> S -> Word64
263−readWord64be n s@(S _ o)
264− -- 8 or fewer bits, use readWord8
265− | n <= 8 = fromIntegral (readWord8 n s)
266−
267− -- 16 or fewer bits, use readWord16be
268− | n <= 16 = fromIntegral (readWord16be n s)
269−
270− | o == 0 = readWithoutOffset s shiftl_w64 shiftr_w64 n
271−
272− | n <= 64 = readWithOffset s shiftl_w64 shiftr_w64 n
273−
274− | otherwise = error "readWord64be: tried to read more than 64 bits"
275−
276−
182+readBool (S bs o bo) = case bo of
183+ BB -> testBit (unsafeHead bs) (7-o)
184+ BL -> testBit (unsafeHead bs) (7-o)
185+ LL -> testBit (unsafeHead bs) o
186+ LB -> testBit (unsafeHead bs) o
187+
188+-- | Read a single bit
189+readBool# :: S -> Int
190+readBool# (S bs (I# o) bo) = case bo of
191+ BB -> testBit# (7# -# o)
192+ BL -> testBit# (7# -# o)
193+ LL -> testBit# o
194+ LB -> testBit# o
195+ where
196+ !(W8# w) = unsafeHead bs
197+ testBit# n = I# (((w `andWord8#` (wordToWord8# 1## `uncheckedShiftLWord8#` n)) `eqWord8#` wordToWord8# 0##) `xorI#` 1#)
198+
199+
200+-- | Extract a range of bits from (ws :: ByteString)
201+--
202+-- Constraint: 8 * (length ws -1 ) < o+n <= 8 * length ws
203+extract :: (Num a, FastBits a) => BitOrder -> ByteString -> Int -> Int -> a
204+extract bo bs o n
205+ | n == 0 = 0
206+ | B.length bs == 0 = error "Empty ByteString"
207+ | otherwise = rev . mask n . foldlWithIndex' f 0 $ bs
208+ where
209+ -- B.foldl' with index
210+ foldlWithIndex' op b = fst . B.foldl' g (b,0)
211+ where g (b',i) w = (op b' w i, (i+1))
212+
213+ -- 'or' correctly shifted words
214+ f b w i = b .|. (fromIntegral w `fastShift` off i)
215+
216+ -- co-offset
217+ r = B.length bs * 8 - (o + n)
218+
219+ -- shift offset depending on the byte position (0..B.length-1)
220+ off i = case bo of
221+ LL -> 8*i - o
222+ LB -> 8*i - o
223+ BB -> (B.length bs -1 - i) * 8 - r
224+ BL -> (B.length bs -1 - i) * 8 - r
225+
226+ -- reverse bits if necessary
227+ rev = case bo of
228+ LB -> reverseBits n
229+ BL -> reverseBits n
230+ BB -> id
231+ LL -> id
232+
233+
234+-- | Generic readWord
235+readWord :: (Num a, FastBits a) => Int -> S -> a
236+readWord n (S bs o bo)
237+ | n == 0 = 0
238+ | otherwise = extract bo (unsafeTake nbytes bs) o n
239+ where nbytes = byte_offset (o+n+7)
240+
241+-- | Check that the number of bits to read is not greater than the first parameter
242+{-# INLINE readWordChecked #-}
243+readWordChecked :: (Num a, FastBits a) => Int -> Int -> S -> a
244+readWordChecked m n s
245+ | n > m = error $ "Tried to read more than " ++ show m ++ " bits (" ++ show n ++")"
246+ | otherwise = readWord n s
247+
248+-- | Read the given number of bytes and return them in Big-Endian order
249+--
250+-- Examples:
251+-- BB: xxxABCDE FGHIJKLM NOPxxxxx -> ABCDEFGH IJKLMNOP
252+-- LL: LMNOPxxx DEFGHIJK xxxxxABC -> ABCDEFGH IJKLMNOP
253+-- BL: xxxPONML KJIHGFED CBAxxxxx -> ABCDEFGH IJKLMNOP
254+-- LB: EDCBAxxx MLKJIHGF xxxxxPON -> ABCDEFGH IJKLMNOP
277255readByteString :: Int -> S -> ByteString
278−readByteString n s@(S bs o)
279− -- no offset, easy.
280− | o == 0 = unsafeTake n bs
281− -- offset. ugg. this is really naive and slow. but also pretty easy :)
282− | otherwise = B.pack (P.map (readWord8 8) (P.take n (iterate (incS 8) s)))
283−
284−readWithoutOffset :: (Bits a, Num a)
285− => S -> (a -> Int -> a) -> (a -> Int -> a) -> Int -> a
286−readWithoutOffset (S bs o) shifterL shifterR n
287− | o /= 0 = error "readWithoutOffset: there is an offset"
288−
289− | bit_offset n == 0 && byte_offset n <= 4 =
290− let segs = byte_offset n
291− bn 0 = fromIntegral (unsafeHead bs)
292− bn n = (bn (n-1) `shifterL` 8) .|. fromIntegral (unsafeIndex bs n)
293−
294− in bn (segs-1)
256+readByteString n (S bs o bo) =
257+ let
258+ bs' = unsafeTake (n+1) bs
259+ bs'' = unsafeTake n bs
260+ rev = B.map (reverseBits 8)
261+ in case (o,bo) of
262+ (0,BB) -> bs''
263+ (0,LL) -> B.reverse bs''
264+ (0,LB) -> rev bs''
265+ (0,BL) -> rev . B.reverse $ bs''
266+ (_,LL) -> readByteString n (S (B.reverse bs') (8-o) BB)
267+ (_,BL) -> rev . B.reverse $ readByteString n (S bs' o BB)
268+ (_,LB) -> rev . B.reverse $ readByteString n (S bs' o LL)
269+ (_,BB) -> unsafePerformIO $ do
270+ let len = n+1
271+ ptr <- mallocBytes len
272+ let f r i = do
273+ let
274+ w = unsafeIndex bs (len-i)
275+ w' = (w `fastShiftL` o) .|. r
276+ r' = w `fastShiftR` (8-o)
277+ poke (ptr `plusPtr` (len-i)) w'
278+ return r'
279+ foldM_ f 0 [1..len]
280+ unsafeInit <$> unsafePackMallocCStringLen (ptr,len)
295281
296− | n <= 64 = let segs = byte_offset n
297− o' = bit_offset (n - 8 + o)
298−
299− bn 0 = fromIntegral (unsafeHead bs)
300− bn n = (bn (n-1) `shifterL` 8) .|. fromIntegral (unsafeIndex bs n)
301−
302− msegs = bn (segs-1) `shifterL` o'
303−
304− last = (fromIntegral (unsafeIndex bs segs)) `shifterR` (8 - o')
305−
306− w = msegs .|. last
307− in w
308−
309−readWithOffset :: (Bits a, Num a)
310− => S -> (a -> Int -> a) -> (a -> Int -> a) -> Int -> a
311−readWithOffset (S bs o) shifterL shifterR n
312− | n <= 64 = let bits_in_msb = 8 - o
313− (n',top) = (n - bits_in_msb
314− , (fromIntegral (unsafeHead bs) .&. make_mask bits_in_msb) `shifterL` n')
315−
316− segs = byte_offset n'
317−
318− bn 0 = 0
319− bn n = (bn (n-1) `shifterL` 8) .|. fromIntegral (unsafeIndex bs n)
320−
321− o' = bit_offset n'
322−
323− mseg = bn segs `shifterL` o'
324−
325− last | o' > 0 = (fromIntegral (unsafeIndex bs (segs + 1))) `shifterR` (8 - o')
326− | otherwise = 0
327−
328− w = top .|. mseg .|. last
329− in w
330282
331283------------------------------------------------------------------------
332284-- | 'BitGet' is a monad, applicative and a functor. See 'runBitGet'
@@ -335,7 +287,6 @@ newtype BitGet a = B { runState :: S -> Get (S,a) }
335287
336288instance Monad BitGet where
337289 return x = B $ \s -> return (s,x)
338− fail str = B $ \_s -> fail str
339290 (B f) >>= g = B $ \s -> do (s',a) <- f s
340291 runState (g a) s'
341292
@@ -346,124 +297,200 @@ instance Applicative BitGet where
346297 pure x = return x
347298 fm <*> m = fm >>= \f -> m >>= \v -> return (f v)
348299
300+instance BitOrderable BitGet where
301+ setBitOrder bo = do
302+ (S bs o _) <- getState
303+ putState (S bs o bo)
304+
305+ getBitOrder = do
306+ (S _ _ bo) <- getState
307+ return bo
308+
309+instance Alignable BitGet where
310+ -- | Skip the given number of bits
311+ skipBits n = do
312+ ensureBits n
313+ withState (incS n)
314+
315+ -- | Skip bits if necessary to align to the next byte
316+ alignByte = do
317+ (S _ o _) <- getState
318+ when (o /= 0) $
319+ skipBits (8-o)
320+
321+
322+
349323-- | Run a 'BitGet' within the Binary packages 'Get' monad. If a byte has
350324-- been partially consumed it will be discarded once 'runBitGet' is finished.
351325runBitGet :: BitGet a -> Get a
352326runBitGet bg = do
353− (_,a) <- runState bg (S B.empty 0)
327+ s <- mkInitState
328+ (s',a) <- runState bg s
329+ putBackState s'
354330 return a
355331
332+mkInitState :: Get S
333+mkInitState = do
334+ bs <- get
335+ put B.empty
336+ return (S bs 0 BB)
337+
338+putBackState :: S -> Get ()
339+putBackState (S bs o _) = do
340+ remaining <- get
341+ let bs' = case o of
342+ 0 -> bs
343+ _ -> unsafeDrop 1 bs
344+ put (bs' `B.append` remaining)
345+
356346getState :: BitGet S
357347getState = B $ \s -> return (s,s)
358348
359349putState :: S -> BitGet ()
360350putState s = B $ \_ -> return (s,())
361351
362−modifyState :: (S -> (S,a)) -> BitGet a
363−modifyState f = B $ \s -> return (f s)
352+withState :: (S -> S) -> BitGet ()
353+withState f = do
354+ s <- getState
355+ putState $! f s
364356
365357-- | Make sure there are at least @n@ bits.
366358ensureBits :: Int -> BitGet ()
367359ensureBits n = do
368− (S bs o) <- getState
360+ (S bs o bo) <- getState
369361 if n <= (B.length bs * 8 - o)
370362 then return ()
371363 else do let currentBits = B.length bs * 8 - o
372− let byteCount = (n - currentBits + 7) `div` 8
373− B $ \_ -> do bs' <- B.getByteString byteCount
374− return (S (bs`append`bs') o, ())
364+ let byteCount = byte_offset (n - currentBits + 7)
365+ B $ \_ -> do B.ensureN byteCount
366+ bs' <- B.get
367+ put B.empty
368+ return (S (bs`append`bs') o bo, ())
369+
370+-- | Test whether all input has been consumed, i.e. there are no remaining
371+-- undecoded bytes.
372+isEmpty :: BitGet Bool
373+isEmpty = B $ \ (S bs o bo) -> if B.null bs
374+ then B.isEmpty >>= \e -> return (S bs o bo, e)
375+ else return (S bs o bo, False)
375376
376377-- | Get 1 bit as a 'Bool'.
377378getBool :: BitGet Bool
378379getBool = block bool
379380
381+-- | Get 1 bit as a 'Bool'.
382+getBool# :: BitGet Int
383+getBool# = block bool#
384+
380385-- | Get @n@ bits as a 'Word8'. @n@ must be within @[0..8]@.
381386getWord8 :: Int -> BitGet Word8
382387getWord8 n = block (word8 n)
383388
384389-- | Get @n@ bits as a 'Word16'. @n@ must be within @[0..16]@.
390+getWord16 :: Int -> BitGet Word16
391+getWord16 n = block (word16 n)
392+
385393getWord16be :: Int -> BitGet Word16
386−getWord16be n = block (word16be n)
394+getWord16be = getWord16
395+{-# DEPRECATED getWord16be "Use 'getWord16' instead" #-}
387396
388397-- | Get @n@ bits as a 'Word32'. @n@ must be within @[0..32]@.
398+getWord32 :: Int -> BitGet Word32
399+getWord32 n = block (word32 n)
400+
389401getWord32be :: Int -> BitGet Word32
390−getWord32be n = block (word32be n)
402+getWord32be = getWord32
403+{-# DEPRECATED getWord32be "Use 'getWord32' instead" #-}
391404
392405-- | Get @n@ bits as a 'Word64'. @n@ must be within @[0..64]@.
406+getWord64 :: Int -> BitGet Word64
407+getWord64 n = block (word64 n)
408+
393409getWord64be :: Int -> BitGet Word64
394−getWord64be n = block (word64be n)
410+getWord64be = getWord64
411+{-# DEPRECATED getWord64be "Use 'getWord64' instead" #-}
395412
396413-- | Get @n@ bytes as a 'ByteString'.
397414getByteString :: Int -> BitGet ByteString
398415getByteString n = block (byteString n)
399416
417+-- | Get @n@ bytes as a lazy ByteString.
418+getLazyByteString :: Int -> BitGet L.ByteString
419+getLazyByteString n = do
420+ (S _ o bo) <- getState
421+ case o of
422+ 0 -> B $ \s -> do
423+ putBackState s
424+ lbs <- B.getLazyByteString (fromIntegral n)
425+ return (S B.empty 0 bo, lbs)
426+ _ -> L.fromChunks . (:[]) <$> Data.Binary.Bits.Get.getByteString n
427+
428+
429+
430+
431+
432+-- | A block that will be read with only one boundary check. Needs to know the
433+-- number of bits in advance.
434+data Block a = Block Int (S -> a)
435+
436+instance Functor Block where
437+ fmap f (Block i p) = Block i (\s -> f (p s))
438+
439+instance Applicative Block where
440+ pure a = Block 0 (\_ -> a)
441+ (Block i p) <*> (Block j q) = Block (i+j) (\s -> p s $ q (incS i s))
442+ (Block i _) *> (Block j q) = Block (i+j) (q . incS i)
443+ (Block i p) <* (Block j _) = Block (i+j) p
444+
445+-- | Get a block. Will be read with one single boundry check, and
446+-- therefore requires a statically known number of bits.
447+-- Build blocks using 'bool', 'word8', 'word16be', 'word32be', 'word64be',
448+-- 'byteString' and 'Applicative'.
449+block :: Block a -> BitGet a
450+block (Block i p) = do
451+ ensureBits i
452+ s <- getState
453+ putState $! (incS i s)
454+ return $! p s
455+
400456-- | Read a 1 bit 'Bool'.
401457bool :: Block Bool
402458bool = Block 1 readBool
403459
460+-- | Read a 1 bit 'Bool'.
461+bool# :: Block Int
462+bool# = Block 1 readBool#
463+
404464-- | Read @n@ bits as a 'Word8'. @n@ must be within @[0..8]@.
405465word8 :: Int -> Block Word8
406−word8 n = Block n (readWord8 n)
466+word8 n = Block n (readWordChecked 8 n)
407467
408468-- | Read @n@ bits as a 'Word16'. @n@ must be within @[0..16]@.
469+word16 :: Int -> Block Word16
470+word16 n = Block n (readWordChecked 16 n)
471+
409472word16be :: Int -> Block Word16
410−word16be n = Block n (readWord16be n)
473+word16be = word16
474+{-# DEPRECATED word16be "Use 'word16' instead" #-}
411475
412476-- | Read @n@ bits as a 'Word32'. @n@ must be within @[0..32]@.
477+word32 :: Int -> Block Word32
478+word32 n = Block n (readWordChecked 32 n)
479+
413480word32be :: Int -> Block Word32
414−word32be n = Block n (readWord32be n)
481+word32be = word32
482+{-# DEPRECATED word32be "Use 'word32' instead" #-}
415483
416484-- | Read @n@ bits as a 'Word64'. @n@ must be within @[0..64]@.
485+word64 :: Int -> Block Word64
486+word64 n = Block n (readWordChecked 64 n)
487+
417488word64be :: Int -> Block Word64
418−word64be n = Block n (readWord64be n)
489+word64be = word64
490+{-# DEPRECATED word64be "Use 'word64' instead" #-}
419491
420492-- | Read @n@ bytes as a 'ByteString'.
421493byteString :: Int -> Block ByteString
422494byteString n | n > 0 = Block (n*8) (readByteString n)
423495 | otherwise = Block 0 (\_ -> B.empty)
424496
425−------------------------------------------------------------------------
426−-- Unchecked shifts, from the package binary
427−
428−shiftl_w16 :: Word16 -> Int -> Word16
429−shiftl_w32 :: Word32 -> Int -> Word32
430−shiftl_w64 :: Word64 -> Int -> Word64
431−
432−#if defined(__GLASGOW_HASKELL__) && !defined(__HADDOCK__)
433−shiftl_w8 (W8# w) (I# i) = W8# (w `uncheckedShiftL#` i)
434−shiftl_w16 (W16# w) (I# i) = W16# (w `uncheckedShiftL#` i)
435−shiftl_w32 (W32# w) (I# i) = W32# (w `uncheckedShiftL#` i)
436−
437−shiftr_w8 (W8# w) (I# i) = W8# (w `uncheckedShiftRL#` i)
438−shiftr_w16 (W16# w) (I# i) = W16# (w `uncheckedShiftRL#` i)
439−shiftr_w32 (W32# w) (I# i) = W32# (w `uncheckedShiftRL#` i)
440−
441−
442−#if WORD_SIZE_IN_BITS < 64
443−shiftl_w64 (W64# w) (I# i) = W64# (w `uncheckedShiftL64#` i)
444−shiftr_w64 (W64# w) (I# i) = W64# (w `uncheckedShiftRL64#` i)
445−
446−#if __GLASGOW_HASKELL__ <= 606
447−-- Exported by GHC.Word in GHC 6.8 and higher
448−foreign import ccall unsafe "stg_uncheckedShiftL64"
449− uncheckedShiftL64# :: Word64# -> Int# -> Word64#
450−foreign import ccall unsafe "stg_uncheckedShiftRL64"
451− uncheckedShiftRL64# :: Word64# -> Int# -> Word64#
452−#endif
453−
454−#else
455−shiftl_w64 (W64# w) (I# i) = W64# (w `uncheckedShiftL#` i)
456−shiftr_w64 (W64# w) (I# i) = W64# (w `uncheckedShiftRL#` i)
457−#endif
458−
459−#else
460−shiftl_w8 = shiftL
461−shiftl_w16 = shiftL
462−shiftl_w32 = shiftL
463−shiftl_w64 = shiftL
464−
465−shiftr_w8 = shiftR
466−shiftr_w16 = shiftR
467−shiftr_w32 = shiftR
468−shiftr_w64 = shiftR
469−#endif