@@ -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
@@ -87,25 +95,28 @@ module Data.Binary.Bits.Get
8795
8896 ) where
8997
90−import Data.Binary.Get as B ( runGet, Get, getByteString, getLazyByteString, isEmpty )
98+import 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.
@@ -154,191 +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 = let w = (fromIntegral (unsafeHead bs) `shiftl_w16` 8) .|.
226− (fromIntegral (unsafeIndex bs 1))
227− m = make_mask n
228− w' = (w `shiftr_w16` (16 - o - n)) .&. m
229− in fromIntegral w'
230−
231−{-# INLINE readWord16be #-}
232−readWord16be :: Int -> S -> Word16
233−readWord16be n s@(S bs o)
234−
235− -- 8 or fewer bits, use readWord8
236− | n <= 8 = fromIntegral (readWord8 n s)
237−
238− -- handle 9 or more bits, stored in two bytes
239−
240− -- no offset, plain and simple 16 bytes
241− | o == 0 && n == 16 = let msb = fromIntegral (unsafeHead bs)
242− lsb = fromIntegral (unsafeIndex bs 1)
243− w = (msb `shiftl_w16` 8) .|. lsb
244− in w
245−
246− -- no offset, but not full 16 bytes
247− | o == 0 = let msb = fromIntegral (unsafeHead bs)
248− lsb = fromIntegral (unsafeIndex bs 1)
249− w = (msb `shiftl_w16` (n-8)) .|. (lsb `shiftr_w16` (16-n))
250− in w
251−
252− -- with offset, and n=9-16
253− | n <= 16 = readWithOffset s shiftl_w16 shiftr_w16 n
254−
255− | otherwise = error "readWord16be: tried to read more than 16 bits"
256−
257−{-# INLINE readWord32be #-}
258−readWord32be :: Int -> S -> Word32
259−readWord32be n s@(S _ o)
260− -- 8 or fewer bits, use readWord8
261− | n <= 8 = fromIntegral (readWord8 n s)
262−
263− -- 16 or fewer bits, use readWord16be
264− | n <= 16 = fromIntegral (readWord16be n s)
265−
266− | o == 0 = readWithoutOffset s shiftl_w32 shiftr_w32 n
267−
268− | n <= 32 = readWithOffset s shiftl_w32 shiftr_w32 n
269−
270− | otherwise = error "readWord32be: tried to read more than 32 bits"
271−
272−
273−{-# INLINE readWord64be #-}
274−readWord64be :: Int -> S -> Word64
275−readWord64be n s@(S _ o)
276− -- 8 or fewer bits, use readWord8
277− | n <= 8 = fromIntegral (readWord8 n s)
278−
279− -- 16 or fewer bits, use readWord16be
280− | n <= 16 = fromIntegral (readWord16be n s)
281−
282− | o == 0 = readWithoutOffset s shiftl_w64 shiftr_w64 n
283−
284− | n <= 64 = readWithOffset s shiftl_w64 shiftr_w64 n
285−
286− | otherwise = error "readWord64be: tried to read more than 64 bits"
287−
288−
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
289255readByteString :: Int -> S -> ByteString
290−readByteString n s@(S bs o)
291− -- no offset, easy.
292− | o == 0 = unsafeTake n bs
293− -- offset. ugg. this is really naive and slow. but also pretty easy :)
294− | otherwise = B.pack (P.map (readWord8 8) (P.take n (iterate (incS 8) s)))
295−
296−readWithoutOffset :: (Bits a, Num a)
297− => S -> (a -> Int -> a) -> (a -> Int -> a) -> Int -> a
298−readWithoutOffset (S bs o) shifterL shifterR n
299− | o /= 0 = error "readWithoutOffset: there is an offset"
300−
301− | bit_offset n == 0 && byte_offset n <= 4 =
302− let segs = byte_offset n
303− bn 0 = fromIntegral (unsafeHead bs)
304− bn n = (bn (n-1) `shifterL` 8) .|. fromIntegral (unsafeIndex bs n)
305−
306− in bn (segs-1)
307−
308− | n <= 64 = let segs = byte_offset n
309− o' = bit_offset (n - 8 + o)
310−
311− bn 0 = fromIntegral (unsafeHead bs)
312− bn n = (bn (n-1) `shifterL` 8) .|. fromIntegral (unsafeIndex bs n)
313−
314− msegs = bn (segs-1) `shifterL` o'
315−
316− last = (fromIntegral (unsafeIndex bs segs)) `shifterR` (8 - o')
317−
318− w = msegs .|. last
319− 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)
320281
321−readWithOffset :: (Bits a, Num a)
322− => S -> (a -> Int -> a) -> (a -> Int -> a) -> Int -> a
323−readWithOffset (S bs o) shifterL shifterR n
324− | n <= 64 = let bits_in_msb = 8 - o
325− (n',top) = (n - bits_in_msb
326− , (fromIntegral (unsafeHead bs) .&. make_mask bits_in_msb) `shifterL` n')
327−
328− segs = byte_offset n'
329−
330− bn 0 = 0
331− bn n = (bn (n-1) `shifterL` 8) .|. fromIntegral (unsafeIndex bs n)
332−
333− o' = bit_offset n'
334−
335− mseg = bn segs `shifterL` o'
336−
337− last | o' > 0 = (fromIntegral (unsafeIndex bs (segs + 1))) `shifterR` (8 - o')
338− | otherwise = 0
339−
340− w = top .|. mseg .|. last
341− in w
342282
343283------------------------------------------------------------------------
344284-- | 'BitGet' is a monad, applicative and a functor. See 'runBitGet'
@@ -347,7 +287,6 @@ newtype BitGet a = B { runState :: S -> Get (S,a) }
347287
348288instance Monad BitGet where
349289 return x = B $ \s -> return (s,x)
350− fail str = B $ \(S inp n) -> putBackState inp n >> fail str
351290 (B f) >>= g = B $ \s -> do (s',a) <- f s
352291 runState (g a) s'
353292
@@ -358,25 +297,51 @@ instance Applicative BitGet where
358297 pure x = return x
359298 fm <*> m = fm >>= \f -> m >>= \v -> return (f v)
360299
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+
361323-- | Run a 'BitGet' within the Binary packages 'Get' monad. If a byte has
362324-- been partially consumed it will be discarded once 'runBitGet' is finished.
363325runBitGet :: BitGet a -> Get a
364326runBitGet bg = do
365327 s <- mkInitState
366− ((S str' n),a) <- runState bg s
367− putBackState str' n
328+ (s',a) <- runState bg s
329+ putBackState s'
368330 return a
369331
370332mkInitState :: Get S
371333mkInitState = do
372− str <- get
334+ bs <- get
373335 put B.empty
374− return (S str 0)
336+ return (S bs 0 BB)
375337
376−putBackState :: B.ByteString -> Int -> Get ()
377−putBackState bs n = do
338+putBackState :: S -> Get ()
339+putBackState (S bs o _) = do
378340 remaining <- get
379− 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)
380345
381346getState :: BitGet S
382347getState = B $ \s -> return (s,s)
@@ -384,52 +349,66 @@ getState = B $ \s -> return (s,s)
384349putState :: S -> BitGet ()
385350putState s = B $ \_ -> return (s,())
386351
352+withState :: (S -> S) -> BitGet ()
353+withState f = do
354+ s <- getState
355+ putState $! f s
356+
387357-- | Make sure there are at least @n@ bits.
388358ensureBits :: Int -> BitGet ()
389359ensureBits n = do
390− (S bs o) <- getState
360+ (S bs o bo) <- getState
391361 if n <= (B.length bs * 8 - o)
392362 then return ()
393363 else do let currentBits = B.length bs * 8 - o
394− let byteCount = (n - currentBits + 7) `div` 8
364+ let byteCount = byte_offset (n - currentBits + 7)
395365 B $ \_ -> do B.ensureN byteCount
396366 bs' <- B.get
397367 put B.empty
398− return (S (bs`append`bs') o, ())
399−
400−-- | Skip the given number of bits
401−skipBits :: Int -> BitGet ()
402−skipBits n = do
403− ensureBits n
404− s <- getState
405− putState $! (incS n s)
368+ return (S (bs`append`bs') o bo, ())
406369
407−-- | Skip bits if necessary to align on a byte
408−alignByte :: BitGet ()
409−alignByte = do
410− (S _ n) <- getState
411− when (n /= 0) $
412− 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)
413376
414377-- | Get 1 bit as a 'Bool'.
415378getBool :: BitGet Bool
416379getBool = block bool
417380
381+-- | Get 1 bit as a 'Bool'.
382+getBool# :: BitGet Int
383+getBool# = block bool#
384+
418385-- | Get @n@ bits as a 'Word8'. @n@ must be within @[0..8]@.
419386getWord8 :: Int -> BitGet Word8
420387getWord8 n = block (word8 n)
421388
422389-- | Get @n@ bits as a 'Word16'. @n@ must be within @[0..16]@.
390+getWord16 :: Int -> BitGet Word16
391+getWord16 n = block (word16 n)
392+
423393getWord16be :: Int -> BitGet Word16
424−getWord16be n = block (word16be n)
394+getWord16be = getWord16
395+{-# DEPRECATED getWord16be "Use 'getWord16' instead" #-}
425396
426397-- | Get @n@ bits as a 'Word32'. @n@ must be within @[0..32]@.
398+getWord32 :: Int -> BitGet Word32
399+getWord32 n = block (word32 n)
400+
427401getWord32be :: Int -> BitGet Word32
428−getWord32be n = block (word32be n)
402+getWord32be = getWord32
403+{-# DEPRECATED getWord32be "Use 'getWord32' instead" #-}
429404
430405-- | Get @n@ bits as a 'Word64'. @n@ must be within @[0..64]@.
406+getWord64 :: Int -> BitGet Word64
407+getWord64 n = block (word64 n)
408+
431409getWord64be :: Int -> BitGet Word64
432−getWord64be n = block (word64be n)
410+getWord64be = getWord64
411+{-# DEPRECATED getWord64be "Use 'getWord64' instead" #-}
433412
434413-- | Get @n@ bytes as a 'ByteString'.
435414getByteString :: Int -> BitGet ByteString
@@ -438,88 +417,80 @@ getByteString n = block (byteString n)
438417-- | Get @n@ bytes as a lazy ByteString.
439418getLazyByteString :: Int -> BitGet L.ByteString
440419getLazyByteString n = do
441− (S _ o) <- getState
420+ (S _ o bo) <- getState
442421 case o of
443− 0 -> B $ \ (S bs o') -> do
444− putBackState bs o'
422+ 0 -> B $ \s -> do
423+ putBackState s
445424 lbs <- B.getLazyByteString (fromIntegral n)
446− return (S B.empty 0, lbs)
425+ return (S B.empty 0 bo, lbs)
447426 _ -> L.fromChunks . (:[]) <$> Data.Binary.Bits.Get.getByteString n
448427
449−-- | Test whether all input has been consumed, i.e. there are no remaining
450−-- undecoded bytes.
451−isEmpty :: BitGet Bool
452−isEmpty = B $ \ (S bs o) -> if B.null bs
453− then B.isEmpty >>= \e -> return (S bs o, e)
454− 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
455455
456456-- | Read a 1 bit 'Bool'.
457457bool :: Block Bool
458458bool = Block 1 readBool
459459
460+-- | Read a 1 bit 'Bool'.
461+bool# :: Block Int
462+bool# = Block 1 readBool#
463+
460464-- | Read @n@ bits as a 'Word8'. @n@ must be within @[0..8]@.
461465word8 :: Int -> Block Word8
462−word8 n = Block n (readWord8 n)
466+word8 n = Block n (readWordChecked 8 n)
463467
464468-- | 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+
465472word16be :: Int -> Block Word16
466−word16be n = Block n (readWord16be n)
473+word16be = word16
474+{-# DEPRECATED word16be "Use 'word16' instead" #-}
467475
468476-- | 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+
469480word32be :: Int -> Block Word32
470−word32be n = Block n (readWord32be n)
481+word32be = word32
482+{-# DEPRECATED word32be "Use 'word32' instead" #-}
471483
472484-- | 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+
473488word64be :: Int -> Block Word64
474−word64be n = Block n (readWord64be n)
489+word64be = word64
490+{-# DEPRECATED word64be "Use 'word64' instead" #-}
475491
476492-- | Read @n@ bytes as a 'ByteString'.
477493byteString :: Int -> Block ByteString
478494byteString n | n > 0 = Block (n*8) (readByteString n)
479495 | otherwise = Block 0 (\_ -> B.empty)
480496
481−------------------------------------------------------------------------
482−-- Unchecked shifts, from the package binary
483−
484−shiftl_w16 :: Word16 -> Int -> Word16
485−shiftl_w32 :: Word32 -> Int -> Word32
486−shiftl_w64 :: Word64 -> Int -> Word64
487−
488−#if defined(__GLASGOW_HASKELL__) && !defined(__HADDOCK__)
489−shiftl_w8 (W8# w) (I# i) = W8# (w `uncheckedShiftL#` i)
490−shiftl_w16 (W16# w) (I# i) = W16# (w `uncheckedShiftL#` i)
491−shiftl_w32 (W32# w) (I# i) = W32# (w `uncheckedShiftL#` i)
492−
493−shiftr_w8 (W8# w) (I# i) = W8# (w `uncheckedShiftRL#` i)
494−shiftr_w16 (W16# w) (I# i) = W16# (w `uncheckedShiftRL#` i)
495−shiftr_w32 (W32# w) (I# i) = W32# (w `uncheckedShiftRL#` i)
496−
497−
498−#if WORD_SIZE_IN_BITS < 64
499−shiftl_w64 (W64# w) (I# i) = W64# (w `uncheckedShiftL64#` i)
500−shiftr_w64 (W64# w) (I# i) = W64# (w `uncheckedShiftRL64#` i)
501−
502−#if __GLASGOW_HASKELL__ <= 606
503−-- Exported by GHC.Word in GHC 6.8 and higher
504−foreign import ccall unsafe "stg_uncheckedShiftL64"
505− uncheckedShiftL64# :: Word64# -> Int# -> Word64#
506−foreign import ccall unsafe "stg_uncheckedShiftRL64"
507− uncheckedShiftRL64# :: Word64# -> Int# -> Word64#
508−#endif
509−
510−#else
511−shiftl_w64 (W64# w) (I# i) = W64# (w `uncheckedShiftL#` i)
512−shiftr_w64 (W64# w) (I# i) = W64# (w `uncheckedShiftRL#` i)
513−#endif
514−
515−#else
516−shiftl_w8 = shiftL
517−shiftl_w16 = shiftL
518−shiftl_w32 = shiftL
519−shiftl_w64 = shiftL
520−
521−shiftr_w8 = shiftR
522−shiftr_w16 = shiftR
523−shiftr_w32 = shiftR
524−shiftr_w64 = shiftR
525−#endif