@@ -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
@@ -59,7 +60,11 @@ 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
@@ -77,6 +82,9 @@ module Data.Binary.Bits.Get
7782 -- ** Read in Blocks
7883 , bool
7984 , word8
85+ , word16
86+ , word32
87+ , word64
8088 , word16be
8189 , word32be
8290 , word64be
@@ -89,23 +97,26 @@ module Data.Binary.Bits.Get
8997
9098import Data.Binary.Get as B ( Get, getLazyByteString, isEmpty )
9199import 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
92103
93104import Data.ByteString as B
94105import qualified Data.ByteString.Lazy as L
95106import Data.ByteString.Unsafe
107+import Foreign.Marshal.Alloc (mallocBytes)
108+import Foreign.Ptr
109+import Foreign.Storable (poke)
110+import System.IO.Unsafe (unsafePerformIO)
96111
97112import Data.Bits
98113import Data.Word
99114import Control.Applicative
100−import Control.Monad (when)
115+import Control.Monad (when,foldM_)
101116
102117import Prelude as P
103−
104−#if defined(__GLASGOW_HASKELL__) && !defined(__HADDOCK__)
105−import GHC.Base
106118import GHC.Word
107−#endif
108−
119+import GHC.Base (uncheckedShiftLWord8#, wordToWord8#, Int (..), andWord8#, Word8#, (-#), Int#, xorI#, eqWord8#, TYPE)
109120
110121-- $bitget
111122-- Parse bits using a monad.
@@ -154,195 +165,120 @@ import GHC.Word
154165-- @
155166
156167data S = S {-# UNPACK #-} !ByteString -- Input
157− {-# UNPACK #-} !Int -- Bit offset (0-7)
168+ {-# UNPACK #-} !Int -- Bit offset (0-7)
169+ !BitOrder -- Bit order
158170 deriving (Show)
159171
160−-- | A block that will be read with only one boundry check. Needs to know the
161−-- number of bits in advance.
162−data Block a = Block Int (S -> a)
163−
164−instance Functor Block where
165− fmap f (Block i p) = Block i (\s -> f (p s))
166−
167−instance Applicative Block where
168− pure a = Block 0 (\_ -> a)
169− (Block i p) <*> (Block j q) = Block (i+j) (\s -> p s $ q (incS i s))
170− (Block i _) *> (Block j q) = Block (i+j) (q . incS i)
171− (Block i p) <* (Block j _) = Block (i+j) p
172−
173−-- | Get a block. Will be read with one single boundry check, and
174−-- therefore requires a statically known number of bits.
175−-- Build blocks using 'bool', 'word8', 'word16be', 'word32be', 'word64be',
176−-- 'byteString' and 'Applicative'.
177−block :: Block a -> BitGet a
178−block (Block i p) = do
179− ensureBits i
180− s <- getState
181− putState $! (incS i s)
182− return $! p s
183−
172+-- | Increment the current bit offset
184173incS :: Int -> S -> S
185−incS o (S bs n) =
186− let !o' = (n+o)
187− !d = o' `shiftR` 3
188− !n' = o' .&. make_mask 3
189− in S (unsafeDrop d bs) n'
190−
191−-- | make_mask 3 = 00000111
192−make_mask :: (Bits a, Num a) => Int -> a
193−make_mask n = (1 `shiftL` fromIntegral n) - 1
194−{-# SPECIALIZE make_mask :: Int -> Int #-}
195−{-# SPECIALIZE make_mask :: Int -> Word #-}
196−{-# SPECIALIZE make_mask :: Int -> Word8 #-}
197−{-# SPECIALIZE make_mask :: Int -> Word16 #-}
198−{-# SPECIALIZE make_mask :: Int -> Word32 #-}
199−{-# SPECIALIZE make_mask :: Int -> Word64 #-}
200−
201−bit_offset :: Int -> Int
202−bit_offset n = make_mask 3 .&. n
203−
204−byte_offset :: Int -> Int
205−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'
206179
180+-- | Read a single bit
207181readBool :: S -> Bool
208−readBool (S bs n) = testBit (unsafeHead bs) (7-n)
209−
210−{-# INLINE readWord8 #-}
211−readWord8 :: Int -> S -> Word8
212−readWord8 n (S bs o)
213− -- no bits at all, return 0
214− | n == 0 = 0
215−
216− -- all bits are in the same byte
217− -- we just need to shift and mask them right
218− | n <= 8 - o = let w = unsafeHead bs
219− m = make_mask n
220− w' = (w `shiftr_w8` (8 - o - n)) .&. m
221− in w'
222−
223− -- the bits are in two different bytes
224− -- make a word16 using both bytes, and then shift and mask
225− -- n <= 8
226− | otherwise = let
227− w = (fromIntegral (unsafeHead bs) `shiftl_w16` 8) .|.
228− (fromIntegral (unsafeIndex bs 1))
229− m = make_mask n
230− w' = (w `shiftr_w16` (16 - o - n)) .&. m
231− in fromIntegral w'
232−
233−{-# INLINE readWord16be #-}
234−readWord16be :: Int -> S -> Word16
235−readWord16be n s@(S bs o)
236−
237− -- 8 or fewer bits, use readWord8
238− | n <= 8 = fromIntegral (readWord8 n s)
239−
240− -- handle 9 or more bits, stored in two bytes
241−
242− -- no offset, plain and simple 16 bytes
243− | o == 0 && n == 16 = let msb = fromIntegral (unsafeHead bs)
244− lsb = fromIntegral (unsafeIndex bs 1)
245− w = (msb `shiftl_w16` 8) .|. lsb
246− in w
247−
248− -- no offset, but not full 16 bytes
249− | o == 0 = let msb = fromIntegral (unsafeHead bs)
250− lsb = fromIntegral (unsafeIndex bs 1)
251− w = (msb `shiftl_w16` (n-8)) .|. (lsb `shiftr_w16` (16-n))
252− in w
253−
254− -- with offset, and n=9-16
255− | n <= 16 = readWithOffset s shiftl_w16 shiftr_w16 n
256−
257− | otherwise = error "readWord16be: tried to read more than 16 bits"
258−
259−{-# INLINE readWord32be #-}
260−readWord32be :: Int -> S -> Word32
261−readWord32be n s@(S _ o)
262− -- 8 or fewer bits, use readWord8
263− | n <= 8 = fromIntegral (readWord8 n s)
264−
265− -- 16 or fewer bits, use readWord16be
266− | n <= 16 = fromIntegral (readWord16be n s)
267−
268− | o == 0 = readWithoutOffset s shiftl_w32 shiftr_w32 n
269−
270− | n <= 32 = readWithOffset s shiftl_w32 shiftr_w32 n
271−
272− | otherwise = error "readWord32be: tried to read more than 32 bits"
273−
274−
275−{-# INLINE readWord64be #-}
276−readWord64be :: Int -> S -> Word64
277−readWord64be n s@(S _ o)
278− -- 8 or fewer bits, use readWord8
279− | n <= 8 = fromIntegral (readWord8 n s)
280−
281− -- 16 or fewer bits, use readWord16be
282− | n <= 16 = fromIntegral (readWord16be n s)
283−
284− | o == 0 = readWithoutOffset s shiftl_w64 shiftr_w64 n
285−
286− | n <= 64 = readWithOffset s shiftl_w64 shiftr_w64 n
287−
288− | otherwise = error "readWord64be: tried to read more than 64 bits"
289−
290−
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
291255readByteString :: Int -> S -> ByteString
292−readByteString n s@(S bs o)
293− -- no offset, easy.
294− | o == 0 = unsafeTake n bs
295− -- offset. ugg. this is really naive and slow. but also pretty easy :)
296− | otherwise = B.pack (P.map (readWord8 8) (P.take n (iterate (incS 8) s)))
297−
298−readWithoutOffset :: (Bits a, Num a)
299− => S -> (a -> Int -> a) -> (a -> Int -> a) -> Int -> a
300−readWithoutOffset (S bs o) shifterL shifterR n
301− | o /= 0 = error "readWithoutOffset: there is an offset"
302−
303− | bit_offset n == 0 && byte_offset n <= 4 =
304− let segs = byte_offset n
305− bn 0 = fromIntegral (unsafeHead bs)
306− bn m = (bn (m-1) `shifterL` 8) .|. fromIntegral (unsafeIndex bs m)
307−
308− in bn (segs-1)
309−
310− -- n <= 64
311− | otherwise = let segs = byte_offset n
312− o' = bit_offset (n - 8 + o)
313−
314− bn 0 = fromIntegral (unsafeHead bs)
315− bn m = (bn (m-1) `shifterL` 8) .|. fromIntegral (unsafeIndex bs m)
316−
317− msegs = bn (segs-1) `shifterL` o'
318−
319− lst = (fromIntegral (unsafeIndex bs segs)) `shifterR` (8 - o')
320−
321− w = msegs .|. lst
322− in w
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)
323281
324−readWithOffset :: (Bits a, Num a)
325− => S -> (a -> Int -> a) -> (a -> Int -> a) -> Int -> a
326−readWithOffset (S bs o) shifterL shifterR n
327− | n <= 64 = let bits_in_msb = 8 - o
328− (n',top) = (n - bits_in_msb
329− , (fromIntegral (unsafeHead bs) .&. make_mask bits_in_msb) `shifterL` n')
330−
331− segs = byte_offset n'
332−
333− bn 0 = 0
334− bn m = (bn (m-1) `shifterL` 8) .|. fromIntegral (unsafeIndex bs m)
335−
336− o' = bit_offset n'
337−
338− mseg = bn segs `shifterL` o'
339−
340− lst | o' > 0 = (fromIntegral (unsafeIndex bs (segs + 1))) `shifterR` (8 - o')
341− | otherwise = 0
342−
343− w = top .|. mseg .|. lst
344− in w
345− | otherwise = error $ "Invalid offset (" ++ show n ++ " > 64)"
346282
347283------------------------------------------------------------------------
348284-- | 'BitGet' is a monad, applicative and a functor. See 'runBitGet'
@@ -351,7 +287,6 @@ newtype BitGet a = B { runState :: S -> Get (S,a) }
351287
352288instance Monad BitGet where
353289 return x = B $ \s -> return (s,x)
354− fail str = B $ \(S inp n) -> putBackState inp n >> fail str
355290 (B f) >>= g = B $ \s -> do (s',a) <- f s
356291 runState (g a) s'
357292
@@ -362,25 +297,51 @@ instance Applicative BitGet where
362297 pure x = return x
363298 fm <*> m = fm >>= \f -> m >>= \v -> return (f v)
364299
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+
365323-- | Run a 'BitGet' within the Binary packages 'Get' monad. If a byte has
366324-- been partially consumed it will be discarded once 'runBitGet' is finished.
367325runBitGet :: BitGet a -> Get a
368326runBitGet bg = do
369327 s <- mkInitState
370− ((S str' n),a) <- runState bg s
371− putBackState str' n
328+ (s',a) <- runState bg s
329+ putBackState s'
372330 return a
373331
374332mkInitState :: Get S
375333mkInitState = do
376− str <- get
334+ bs <- get
377335 put B.empty
378− return (S str 0)
336+ return (S bs 0 BB)
379337
380−putBackState :: B.ByteString -> Int -> Get ()
381−putBackState bs n = do
338+putBackState :: S -> Get ()
339+putBackState (S bs o _) = do
382340 remaining <- get
383− put (B.drop (if n==0 then 0 else 1) bs `B.append` remaining)
341+ let bs' = case o of
342+ 0 -> bs
343+ _ -> unsafeDrop 1 bs
344+ put (bs' `B.append` remaining)
384345
385346getState :: BitGet S
386347getState = B $ \s -> return (s,s)
@@ -388,52 +349,66 @@ getState = B $ \s -> return (s,s)
388349putState :: S -> BitGet ()
389350putState s = B $ \_ -> return (s,())
390351
352+withState :: (S -> S) -> BitGet ()
353+withState f = do
354+ s <- getState
355+ putState $! f s
356+
391357-- | Make sure there are at least @n@ bits.
392358ensureBits :: Int -> BitGet ()
393359ensureBits n = do
394− (S bs o) <- getState
360+ (S bs o bo) <- getState
395361 if n <= (B.length bs * 8 - o)
396362 then return ()
397363 else do let currentBits = B.length bs * 8 - o
398− let byteCount = (n - currentBits + 7) `div` 8
364+ let byteCount = byte_offset (n - currentBits + 7)
399365 B $ \_ -> do B.ensureN byteCount
400366 bs' <- B.get
401367 put B.empty
402− return (S (bs`append`bs') o, ())
403−
404−-- | Skip the given number of bits
405−skipBits :: Int -> BitGet ()
406−skipBits n = do
407− ensureBits n
408− s <- getState
409− putState $! (incS n s)
368+ return (S (bs`append`bs') o bo, ())
410369
411−-- | Skip bits if necessary to align on a byte
412−alignByte :: BitGet ()
413−alignByte = do
414− (S _ n) <- getState
415− when (n /= 0) $
416− skipBits (8-n)
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)
417376
418377-- | Get 1 bit as a 'Bool'.
419378getBool :: BitGet Bool
420379getBool = block bool
421380
381+-- | Get 1 bit as a 'Bool'.
382+getBool# :: BitGet Int
383+getBool# = block bool#
384+
422385-- | Get @n@ bits as a 'Word8'. @n@ must be within @[0..8]@.
423386getWord8 :: Int -> BitGet Word8
424387getWord8 n = block (word8 n)
425388
426389-- | Get @n@ bits as a 'Word16'. @n@ must be within @[0..16]@.
390+getWord16 :: Int -> BitGet Word16
391+getWord16 n = block (word16 n)
392+
427393getWord16be :: Int -> BitGet Word16
428−getWord16be n = block (word16be n)
394+getWord16be = getWord16
395+{-# DEPRECATED getWord16be "Use 'getWord16' instead" #-}
429396
430397-- | Get @n@ bits as a 'Word32'. @n@ must be within @[0..32]@.
398+getWord32 :: Int -> BitGet Word32
399+getWord32 n = block (word32 n)
400+
431401getWord32be :: Int -> BitGet Word32
432−getWord32be n = block (word32be n)
402+getWord32be = getWord32
403+{-# DEPRECATED getWord32be "Use 'getWord32' instead" #-}
433404
434405-- | Get @n@ bits as a 'Word64'. @n@ must be within @[0..64]@.
406+getWord64 :: Int -> BitGet Word64
407+getWord64 n = block (word64 n)
408+
435409getWord64be :: Int -> BitGet Word64
436−getWord64be n = block (word64be n)
410+getWord64be = getWord64
411+{-# DEPRECATED getWord64be "Use 'getWord64' instead" #-}
437412
438413-- | Get @n@ bytes as a 'ByteString'.
439414getByteString :: Int -> BitGet ByteString
@@ -442,91 +417,80 @@ getByteString n = block (byteString n)
442417-- | Get @n@ bytes as a lazy ByteString.
443418getLazyByteString :: Int -> BitGet L.ByteString
444419getLazyByteString n = do
445− (S _ o) <- getState
420+ (S _ o bo) <- getState
446421 case o of
447− 0 -> B $ \ (S bs o') -> do
448− putBackState bs o'
422+ 0 -> B $ \s -> do
423+ putBackState s
449424 lbs <- B.getLazyByteString (fromIntegral n)
450− return (S B.empty 0, lbs)
425+ return (S B.empty 0 bo, lbs)
451426 _ -> L.fromChunks . (:[]) <$> Data.Binary.Bits.Get.getByteString n
452427
453−-- | Test whether all input has been consumed, i.e. there are no remaining
454−-- undecoded bytes.
455−isEmpty :: BitGet Bool
456−isEmpty = B $ \ (S bs o) -> if B.null bs
457− then B.isEmpty >>= \e -> return (S bs o, e)
458− else return (S bs o, False)
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
459455
460456-- | Read a 1 bit 'Bool'.
461457bool :: Block Bool
462458bool = Block 1 readBool
463459
460+-- | Read a 1 bit 'Bool'.
461+bool# :: Block Int
462+bool# = Block 1 readBool#
463+
464464-- | Read @n@ bits as a 'Word8'. @n@ must be within @[0..8]@.
465465word8 :: Int -> Block Word8
466−word8 n = Block n (readWord8 n)
466+word8 n = Block n (readWordChecked 8 n)
467467
468468-- | 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+
469472word16be :: Int -> Block Word16
470−word16be n = Block n (readWord16be n)
473+word16be = word16
474+{-# DEPRECATED word16be "Use 'word16' instead" #-}
471475
472476-- | 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+
473480word32be :: Int -> Block Word32
474−word32be n = Block n (readWord32be n)
481+word32be = word32
482+{-# DEPRECATED word32be "Use 'word32' instead" #-}
475483
476484-- | 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+
477488word64be :: Int -> Block Word64
478−word64be n = Block n (readWord64be n)
489+word64be = word64
490+{-# DEPRECATED word64be "Use 'word64' instead" #-}
479491
480492-- | Read @n@ bytes as a 'ByteString'.
481493byteString :: Int -> Block ByteString
482494byteString n | n > 0 = Block (n*8) (readByteString n)
483495 | otherwise = Block 0 (\_ -> B.empty)
484496
485−------------------------------------------------------------------------
486−-- Unchecked shifts, from the package binary
487−
488−shiftl_w16 :: Word16 -> Int -> Word16
489−shiftl_w32 :: Word32 -> Int -> Word32
490−shiftl_w64 :: Word64 -> Int -> Word64
491−
492−shiftr_w8 :: Word8 -> Int -> Word8
493−shiftr_w16 :: Word16 -> Int -> Word16
494−shiftr_w32 :: Word32 -> Int -> Word32
495−shiftr_w64 :: Word64 -> Int -> Word64
496−
497−#if defined(__GLASGOW_HASKELL__) && !defined(__HADDOCK__)
498−shiftl_w16 (W16# w) (I# i) = W16# (w `uncheckedShiftL#` i)
499−shiftl_w32 (W32# w) (I# i) = W32# (w `uncheckedShiftL#` i)
500−
501−shiftr_w8 (W8# w) (I# i) = W8# (w `uncheckedShiftRL#` i)
502−shiftr_w16 (W16# w) (I# i) = W16# (w `uncheckedShiftRL#` i)
503−shiftr_w32 (W32# w) (I# i) = W32# (w `uncheckedShiftRL#` i)
504−
505−
506−#if WORD_SIZE_IN_BITS < 64
507−shiftl_w64 (W64# w) (I# i) = W64# (w `uncheckedShiftL64#` i)
508−shiftr_w64 (W64# w) (I# i) = W64# (w `uncheckedShiftRL64#` i)
509−
510−#if __GLASGOW_HASKELL__ <= 606
511−-- Exported by GHC.Word in GHC 6.8 and higher
512−foreign import ccall unsafe "stg_uncheckedShiftL64"
513− uncheckedShiftL64# :: Word64# -> Int# -> Word64#
514−foreign import ccall unsafe "stg_uncheckedShiftRL64"
515− uncheckedShiftRL64# :: Word64# -> Int# -> Word64#
516−#endif
517−
518−#else
519−shiftl_w64 (W64# w) (I# i) = W64# (w `uncheckedShiftL#` i)
520−shiftr_w64 (W64# w) (I# i) = W64# (w `uncheckedShiftRL#` i)
521−#endif
522−
523−#else
524−shiftl_w16 = shiftL
525−shiftl_w32 = shiftL
526−shiftl_w64 = shiftL
527−
528−shiftr_w8 = shiftR
529−shiftr_w16 = shiftR
530−shiftr_w32 = shiftR
531−shiftr_w64 = shiftR
532−#endif