{-# LANGUAGE CPP, ForeignFunctionInterface, BangPatterns #-} {-# LANGUAGE UnliftedFFITypes, MagicHash, UnboxedTuples, DeriveDataTypeable #-} #if __GLASGOW_HASKELL__ >= 703 {-# LANGUAGE Unsafe #-} #endif {-# OPTIONS_HADDOCK not-home #-} -- | -- Module : Data.ByteString.Internal -- Copyright : (c) Don Stewart 2006-2008 -- (c) Duncan Coutts 2006-2012 -- License : BSD-style -- Maintainer : dons00@gmail.com, duncan@community.haskell.org -- Stability : unstable -- Portability : non-portable -- -- A module containing semi-public 'ByteString' internals. This exposes the -- 'ByteString' representation and low level construction functions. As such -- all the functions in this module are unsafe. The API is also not stable. -- -- Where possible application should instead use the functions from the normal -- public interface modules, such as "Data.ByteString.Unsafe". Packages that -- extend the ByteString system at a low level will need to use this module. -- module Data.ByteString.Internal ( -- * The @ByteString@ type and representation ByteString(..), -- instances: Eq, Ord, Show, Read, Data, Typeable -- * Conversion with lists: packing and unpacking packBytes, packUptoLenBytes, unsafePackLenBytes, packChars, packUptoLenChars, unsafePackLenChars, unpackBytes, unpackAppendBytesLazy, unpackAppendBytesStrict, unpackChars, unpackAppendCharsLazy, unpackAppendCharsStrict, unsafePackAddress, -- * Low level imperative construction create, -- :: Int -> (Ptr Word8 -> IO ()) -> IO ByteString createUptoN, -- :: Int -> (Ptr Word8 -> IO Int) -> IO ByteString createAndTrim, -- :: Int -> (Ptr Word8 -> IO Int) -> IO ByteString createAndTrim', -- :: Int -> (Ptr Word8 -> IO (Int, Int, a)) -> IO (ByteString, a) unsafeCreate, -- :: Int -> (Ptr Word8 -> IO ()) -> ByteString unsafeCreateUptoN, -- :: Int -> (Ptr Word8 -> IO Int) -> ByteString mallocByteString, -- :: Int -> IO (ForeignPtr a) -- * Conversion to and from ForeignPtrs fromForeignPtr, -- :: ForeignPtr Word8 -> Int -> Int -> ByteString toForeignPtr, -- :: ByteString -> (ForeignPtr Word8, Int, Int) -- * Utilities nullForeignPtr, -- :: ForeignPtr Word8 checkedAdd, -- :: String -> Int -> Int -> Int -- * Standard C Functions c_strlen, -- :: CString -> IO CInt c_free_finalizer, -- :: FunPtr (Ptr Word8 -> IO ()) memchr, -- :: Ptr Word8 -> Word8 -> CSize -> IO Ptr Word8 memcmp, -- :: Ptr Word8 -> Ptr Word8 -> Int -> IO CInt memcpy, -- :: Ptr Word8 -> Ptr Word8 -> Int -> IO () memset, -- :: Ptr Word8 -> Word8 -> CSize -> IO (Ptr Word8) -- * cbits functions c_reverse, -- :: Ptr Word8 -> Ptr Word8 -> CInt -> IO () c_intersperse, -- :: Ptr Word8 -> Ptr Word8 -> CInt -> Word8 -> IO () c_maximum, -- :: Ptr Word8 -> CInt -> IO Word8 c_minimum, -- :: Ptr Word8 -> CInt -> IO Word8 c_count, -- :: Ptr Word8 -> CInt -> Word8 -> IO CInt -- * Chars w2c, c2w, isSpaceWord8, isSpaceChar8, -- * Deprecated and unmentionable accursedUnutterablePerformIO, -- :: IO a -> a inlinePerformIO -- :: IO a -> a ) where import Prelude hiding (concat, null) import qualified Data.List as List import Foreign.ForeignPtr (ForeignPtr, withForeignPtr) import Foreign.Ptr (Ptr, FunPtr, plusPtr) import Foreign.Storable (Storable(..)) #if MIN_VERSION_base(4,5,0) || __GLASGOW_HASKELL__ >= 703 import Foreign.C.Types (CInt(..), CSize(..), CULong(..)) #else import Foreign.C.Types (CInt, CSize, CULong) #endif import Foreign.C.String (CString) #if !(MIN_VERSION_base(4,11,0)) && MIN_VERSION_base(4,9,0) import Data.Semigroup (Semigroup((<>))) #endif #if !(MIN_VERSION_base(4,8,0)) import Data.Monoid (Monoid(..)) #endif import Control.DeepSeq (NFData(rnf)) import Data.String (IsString(..)) import Control.Exception (assert) import Data.Char (ord) import Data.Word (Word8) import Data.Typeable (Typeable) import Data.Data (Data(..), mkNoRepType) import GHC.Base (nullAddr#,realWorld#,unsafeChr) #if MIN_VERSION_base(4,4,0) import GHC.CString (unpackCString#) #else import GHC.Base (unpackCString#) #endif import GHC.Prim (Addr#) #if __GLASGOW_HASKELL__ >= 611 import GHC.IO (IO(IO),unsafeDupablePerformIO) #else import GHC.IOBase (IO(IO),RawBuffer,unsafeDupablePerformIO) #endif import GHC.ForeignPtr (ForeignPtr(ForeignPtr) ,newForeignPtr_, mallocPlainForeignPtrBytes) import GHC.Ptr (Ptr(..), castPtr) -- CFILES stuff is Hugs only {-# CFILES cbits/fpstring.c #-} -- ----------------------------------------------------------------------------- -- | A space-efficient representation of a 'Word8' vector, supporting many -- efficient operations. -- -- A 'ByteString' contains 8-bit bytes, or by using the operations from -- "Data.ByteString.Char8" it can be interpreted as containing 8-bit -- characters. -- data ByteString = PS {-# UNPACK #-} !(ForeignPtr Word8) -- payload {-# UNPACK #-} !Int -- offset {-# UNPACK #-} !Int -- length deriving (Typeable) instance Eq ByteString where (==) = eq instance Ord ByteString where compare = compareBytes #if MIN_VERSION_base(4,9,0) instance Semigroup ByteString where (<>) = append #endif instance Monoid ByteString where mempty = PS nullForeignPtr 0 0 #if MIN_VERSION_base(4,9,0) mappend = (<>) #else mappend = append #endif mconcat = concat instance NFData ByteString where rnf PS{} = () instance Show ByteString where showsPrec p ps r = showsPrec p (unpackChars ps) r instance Read ByteString where readsPrec p str = [ (packChars x, y) | (x, y) <- readsPrec p str ] instance IsString ByteString where fromString = packChars instance Data ByteString where gfoldl f z txt = z packBytes `f` unpackBytes txt toConstr _ = error "Data.ByteString.ByteString.toConstr" gunfold _ _ = error "Data.ByteString.ByteString.gunfold" dataTypeOf _ = mkNoRepType "Data.ByteString.ByteString" ------------------------------------------------------------------------ -- Packing and unpacking from lists packBytes :: [Word8] -> ByteString packBytes ws = unsafePackLenBytes (List.length ws) ws packChars :: [Char] -> ByteString packChars cs = unsafePackLenChars (List.length cs) cs {-# INLINE [0] packChars #-} {-# RULES "ByteString packChars/packAddress" forall s . packChars (unpackCString# s) = accursedUnutterablePerformIO (unsafePackAddress s) #-} unsafePackLenBytes :: Int -> [Word8] -> ByteString unsafePackLenBytes len xs0 = unsafeCreate len $ \p -> go p xs0 where go !_ [] = return () go !p (x:xs) = poke p x >> go (p `plusPtr` 1) xs unsafePackLenChars :: Int -> [Char] -> ByteString unsafePackLenChars len cs0 = unsafeCreate len $ \p -> go p cs0 where go !_ [] = return () go !p (c:cs) = poke p (c2w c) >> go (p `plusPtr` 1) cs -- | /O(n)/ Pack a null-terminated sequence of bytes, pointed to by an -- Addr\# (an arbitrary machine address assumed to point outside the -- garbage-collected heap) into a @ByteString@. A much faster way to -- create an 'Addr#' is with an unboxed string literal, than to pack a -- boxed string. A unboxed string literal is compiled to a static @char -- []@ by GHC. Establishing the length of the string requires a call to -- @strlen(3)@, so the 'Addr#' must point to a null-terminated buffer (as -- is the case with @\"string\"\#@ literals in GHC). Use 'unsafePackAddressLen' -- if you know the length of the string statically. -- -- An example: -- -- > literalFS = unsafePackAddress "literal"# -- -- This function is /unsafe/. If you modify the buffer pointed to by the -- original 'Addr#' this modification will be reflected in the resulting -- @ByteString@, breaking referential transparency. -- -- Note this also won't work if your 'Addr#' has embedded @\'\\0\'@ characters in -- the string, as @strlen@ will return too short a length. -- unsafePackAddress :: Addr# -> IO ByteString unsafePackAddress addr# = do p <- newForeignPtr_ (castPtr cstr) l <- c_strlen cstr return $ PS p 0 (fromIntegral l) where cstr :: CString cstr = Ptr addr# {-# INLINE unsafePackAddress #-} packUptoLenBytes :: Int -> [Word8] -> (ByteString, [Word8]) packUptoLenBytes len xs0 = unsafeCreateUptoN' len $ \p -> go p len xs0 where go !_ !n [] = return (len-n, []) go !_ !0 xs = return (len, xs) go !p !n (x:xs) = poke p x >> go (p `plusPtr` 1) (n-1) xs packUptoLenChars :: Int -> [Char] -> (ByteString, [Char]) packUptoLenChars len cs0 = unsafeCreateUptoN' len $ \p -> go p len cs0 where go !_ !n [] = return (len-n, []) go !_ !0 cs = return (len, cs) go !p !n (c:cs) = poke p (c2w c) >> go (p `plusPtr` 1) (n-1) cs -- Unpacking bytestrings into lists effeciently is a tradeoff: on the one hand -- we would like to write a tight loop that just blats the list into memory, on -- the other hand we want it to be unpacked lazily so we don't end up with a -- massive list data structure in memory. -- -- Our strategy is to combine both: we will unpack lazily in reasonable sized -- chunks, where each chunk is unpacked strictly. -- -- unpackBytes and unpackChars do the lazy loop, while unpackAppendBytes and -- unpackAppendChars do the chunks strictly. unpackBytes :: ByteString -> [Word8] unpackBytes bs = unpackAppendBytesLazy bs [] unpackChars :: ByteString -> [Char] unpackChars bs = unpackAppendCharsLazy bs [] unpackAppendBytesLazy :: ByteString -> [Word8] -> [Word8] unpackAppendBytesLazy (PS fp off len) xs | len <= 100 = unpackAppendBytesStrict (PS fp off len) xs | otherwise = unpackAppendBytesStrict (PS fp off 100) remainder where remainder = unpackAppendBytesLazy (PS fp (off+100) (len-100)) xs -- Why 100 bytes you ask? Because on a 64bit machine the list we allocate -- takes just shy of 4k which seems like a reasonable amount. -- (5 words per list element, 8 bytes per word, 100 elements = 4000 bytes) unpackAppendCharsLazy :: ByteString -> [Char] -> [Char] unpackAppendCharsLazy (PS fp off len) cs | len <= 100 = unpackAppendCharsStrict (PS fp off len) cs | otherwise = unpackAppendCharsStrict (PS fp off 100) remainder where remainder = unpackAppendCharsLazy (PS fp (off+100) (len-100)) cs -- For these unpack functions, since we're unpacking the whole list strictly we -- build up the result list in an accumulator. This means we have to build up -- the list starting at the end. So our traversal starts at the end of the -- buffer and loops down until we hit the sentinal: unpackAppendBytesStrict :: ByteString -> [Word8] -> [Word8] unpackAppendBytesStrict (PS fp off len) xs = accursedUnutterablePerformIO $ withForeignPtr fp $ \base -> loop (base `plusPtr` (off-1)) (base `plusPtr` (off-1+len)) xs where loop !sentinal !p acc | p == sentinal = return acc | otherwise = do x <- peek p loop sentinal (p `plusPtr` (-1)) (x:acc) unpackAppendCharsStrict :: ByteString -> [Char] -> [Char] unpackAppendCharsStrict (PS fp off len) xs = accursedUnutterablePerformIO $ withForeignPtr fp $ \base -> loop (base `plusPtr` (off-1)) (base `plusPtr` (off-1+len)) xs where loop !sentinal !p acc | p == sentinal = return acc | otherwise = do x <- peek p loop sentinal (p `plusPtr` (-1)) (w2c x:acc) ------------------------------------------------------------------------ -- | The 0 pointer. Used to indicate the empty Bytestring. nullForeignPtr :: ForeignPtr Word8 nullForeignPtr = ForeignPtr nullAddr# (error "nullForeignPtr") --TODO: should ForeignPtrContents be strict? -- --------------------------------------------------------------------- -- Low level constructors -- | /O(1)/ Build a ByteString from a ForeignPtr. -- -- If you do not need the offset parameter then you do should be using -- 'Data.ByteString.Unsafe.unsafePackCStringLen' or -- 'Data.ByteString.Unsafe.unsafePackCStringFinalizer' instead. -- fromForeignPtr :: ForeignPtr Word8 -> Int -- ^ Offset -> Int -- ^ Length -> ByteString fromForeignPtr = PS {-# INLINE fromForeignPtr #-} -- | /O(1)/ Deconstruct a ForeignPtr from a ByteString toForeignPtr :: ByteString -> (ForeignPtr Word8, Int, Int) -- ^ (ptr, offset, length) toForeignPtr (PS ps s l) = (ps, s, l) {-# INLINE toForeignPtr #-} -- | A way of creating ByteStrings outside the IO monad. The @Int@ -- argument gives the final size of the ByteString. unsafeCreate :: Int -> (Ptr Word8 -> IO ()) -> ByteString unsafeCreate l f = unsafeDupablePerformIO (create l f) {-# INLINE unsafeCreate #-} -- | Like 'unsafeCreate' but instead of giving the final size of the -- ByteString, it is just an upper bound. The inner action returns -- the actual size. Unlike 'createAndTrim' the ByteString is not -- reallocated if the final size is less than the estimated size. unsafeCreateUptoN :: Int -> (Ptr Word8 -> IO Int) -> ByteString unsafeCreateUptoN l f = unsafeDupablePerformIO (createUptoN l f) {-# INLINE unsafeCreateUptoN #-} unsafeCreateUptoN' :: Int -> (Ptr Word8 -> IO (Int, a)) -> (ByteString, a) unsafeCreateUptoN' l f = unsafeDupablePerformIO (createUptoN' l f) {-# INLINE unsafeCreateUptoN' #-} -- | Create ByteString of size @l@ and use action @f@ to fill it's contents. create :: Int -> (Ptr Word8 -> IO ()) -> IO ByteString create l f = do fp <- mallocByteString l withForeignPtr fp $ \p -> f p return $! PS fp 0 l {-# INLINE create #-} -- | Create ByteString of up to size size @l@ and use action @f@ to fill it's -- contents which returns its true size. createUptoN :: Int -> (Ptr Word8 -> IO Int) -> IO ByteString createUptoN l f = do fp <- mallocByteString l l' <- withForeignPtr fp $ \p -> f p assert (l' <= l) $ return $! PS fp 0 l' {-# INLINE createUptoN #-} -- | Create ByteString of up to size @l@ and use action @f@ to fill it's contents which returns its true size. createUptoN' :: Int -> (Ptr Word8 -> IO (Int, a)) -> IO (ByteString, a) createUptoN' l f = do fp <- mallocByteString l (l', res) <- withForeignPtr fp $ \p -> f p assert (l' <= l) $ return (PS fp 0 l', res) {-# INLINE createUptoN' #-} -- | Given the maximum size needed and a function to make the contents -- of a ByteString, createAndTrim makes the 'ByteString'. The generating -- function is required to return the actual final size (<= the maximum -- size), and the resulting byte array is realloced to this size. -- -- createAndTrim is the main mechanism for creating custom, efficient -- ByteString functions, using Haskell or C functions to fill the space. -- createAndTrim :: Int -> (Ptr Word8 -> IO Int) -> IO ByteString createAndTrim l f = do fp <- mallocByteString l withForeignPtr fp $ \p -> do l' <- f p if assert (l' <= l) $ l' >= l then return $! PS fp 0 l else create l' $ \p' -> memcpy p' p l' {-# INLINE createAndTrim #-} createAndTrim' :: Int -> (Ptr Word8 -> IO (Int, Int, a)) -> IO (ByteString, a) createAndTrim' l f = do fp <- mallocByteString l withForeignPtr fp $ \p -> do (off, l', res) <- f p if assert (l' <= l) $ l' >= l then return (PS fp 0 l, res) else do ps <- create l' $ \p' -> memcpy p' (p `plusPtr` off) l' return (ps, res) -- | Wrapper of 'mallocForeignPtrBytes' with faster implementation for GHC -- mallocByteString :: Int -> IO (ForeignPtr a) mallocByteString = mallocPlainForeignPtrBytes {-# INLINE mallocByteString #-} ------------------------------------------------------------------------ -- Implementations for Eq, Ord and Monoid instances eq :: ByteString -> ByteString -> Bool eq a@(PS fp off len) b@(PS fp' off' len') | len /= len' = False -- short cut on length | fp == fp' && off == off' = True -- short cut for the same string | otherwise = compareBytes a b == EQ {-# INLINE eq #-} -- ^ still needed compareBytes :: ByteString -> ByteString -> Ordering compareBytes (PS _ _ 0) (PS _ _ 0) = EQ -- short cut for empty strings compareBytes (PS fp1 off1 len1) (PS fp2 off2 len2) = accursedUnutterablePerformIO $ withForeignPtr fp1 $ \p1 -> withForeignPtr fp2 $ \p2 -> do i <- memcmp (p1 `plusPtr` off1) (p2 `plusPtr` off2) (min len1 len2) return $! case i `compare` 0 of EQ -> len1 `compare` len2 x -> x append :: ByteString -> ByteString -> ByteString append (PS _ _ 0) b = b append a (PS _ _ 0) = a append (PS fp1 off1 len1) (PS fp2 off2 len2) = unsafeCreate (len1+len2) $ \destptr1 -> do let destptr2 = destptr1 `plusPtr` len1 withForeignPtr fp1 $ \p1 -> memcpy destptr1 (p1 `plusPtr` off1) len1 withForeignPtr fp2 $ \p2 -> memcpy destptr2 (p2 `plusPtr` off2) len2 concat :: [ByteString] -> ByteString concat = \bss0 -> goLen0 bss0 bss0 -- The idea here is we first do a pass over the input list to determine: -- -- 1. is a copy necessary? e.g. @concat []@, @concat [mempty, "hello"]@, -- and @concat ["hello", mempty, mempty]@ can all be handled without -- copying. -- 2. if a copy is necessary, how large is the result going to be? -- -- If a copy is necessary then we create a buffer of the appropriate size -- and do another pass over the input list, copying the chunks into the -- buffer. Also, since foreign calls aren't entirely free we skip over -- empty chunks while copying. -- -- We pass the original [ByteString] (bss0) through as an argument through -- goLen0, goLen1, and goLen since we will need it again in goCopy. Passing -- it as an explicit argument avoids capturing it in these functions' -- closures which would result in unnecessary closure allocation. where -- It's still possible that the result is empty goLen0 _ [] = mempty goLen0 bss0 (PS _ _ 0 :bss) = goLen0 bss0 bss goLen0 bss0 (bs :bss) = goLen1 bss0 bs bss -- It's still possible that the result is a single chunk goLen1 _ bs [] = bs goLen1 bss0 bs (PS _ _ 0 :bss) = goLen1 bss0 bs bss goLen1 bss0 bs (PS _ _ len:bss) = goLen bss0 (checkedAdd "concat" len' len) bss where PS _ _ len' = bs -- General case, just find the total length we'll need goLen bss0 !total (PS _ _ len:bss) = goLen bss0 total' bss where total' = checkedAdd "concat" total len goLen bss0 total [] = unsafeCreate total $ \ptr -> goCopy bss0 ptr -- Copy the data goCopy [] !_ = return () goCopy (PS _ _ 0 :bss) !ptr = goCopy bss ptr goCopy (PS fp off len:bss) !ptr = do withForeignPtr fp $ \p -> memcpy ptr (p `plusPtr` off) len goCopy bss (ptr `plusPtr` len) {-# NOINLINE concat #-} {-# RULES "ByteString concat [] -> mempty" concat [] = mempty "ByteString concat [bs] -> bs" forall x. concat [x] = x #-} -- | Add two non-negative numbers. Errors out on overflow. checkedAdd :: String -> Int -> Int -> Int checkedAdd fun x y | r >= 0 = r | otherwise = overflowError fun where r = x + y {-# INLINE checkedAdd #-} ------------------------------------------------------------------------ -- | Conversion between 'Word8' and 'Char'. Should compile to a no-op. w2c :: Word8 -> Char w2c = unsafeChr . fromIntegral {-# INLINE w2c #-} -- | Unsafe conversion between 'Char' and 'Word8'. This is a no-op and -- silently truncates to 8 bits Chars > '\255'. It is provided as -- convenience for ByteString construction. c2w :: Char -> Word8 c2w = fromIntegral . ord {-# INLINE c2w #-} -- | Selects words corresponding to white-space characters in the Latin-1 range -- ordered by frequency. isSpaceWord8 :: Word8 -> Bool isSpaceWord8 w = w == 0x20 || w == 0x0A || -- LF, \n w == 0x09 || -- HT, \t w == 0x0C || -- FF, \f w == 0x0D || -- CR, \r w == 0x0B || -- VT, \v w == 0xA0 -- spotted by QC.. {-# INLINE isSpaceWord8 #-} -- | Selects white-space characters in the Latin-1 range isSpaceChar8 :: Char -> Bool isSpaceChar8 c = c == ' ' || c == '\t' || c == '\n' || c == '\r' || c == '\f' || c == '\v' || c == '\xa0' {-# INLINE isSpaceChar8 #-} overflowError :: String -> a overflowError fun = error $ "Data.ByteString." ++ fun ++ ": size overflow" ------------------------------------------------------------------------ -- | This \"function\" has a superficial similarity to 'unsafePerformIO' but -- it is in fact a malevolent agent of chaos. It unpicks the seams of reality -- (and the 'IO' monad) so that the normal rules no longer apply. It lulls you -- into thinking it is reasonable, but when you are not looking it stabs you -- in the back and aliases all of your mutable buffers. The carcass of many a -- seasoned Haskell programmer lie strewn at its feet. -- -- Witness the trail of destruction: -- -- * -- -- * -- -- * -- -- * -- -- * -- -- Do not talk about \"safe\"! You do not know what is safe! -- -- Yield not to its blasphemous call! Flee traveller! Flee or you will be -- corrupted and devoured! -- {-# INLINE accursedUnutterablePerformIO #-} accursedUnutterablePerformIO :: IO a -> a accursedUnutterablePerformIO (IO m) = case m realWorld# of (# _, r #) -> r inlinePerformIO :: IO a -> a inlinePerformIO = accursedUnutterablePerformIO {-# INLINE inlinePerformIO #-} {-# DEPRECATED inlinePerformIO "If you think you know what you are doing, use 'unsafePerformIO'. If you are sure you know what you are doing, use 'unsafeDupablePerformIO'. If you enjoy sharing an address space with a malevolent agent of chaos, try 'accursedUnutterablePerformIO'." #-} -- --------------------------------------------------------------------- -- -- Standard C functions -- foreign import ccall unsafe "string.h strlen" c_strlen :: CString -> IO CSize foreign import ccall unsafe "static stdlib.h &free" c_free_finalizer :: FunPtr (Ptr Word8 -> IO ()) foreign import ccall unsafe "string.h memchr" c_memchr :: Ptr Word8 -> CInt -> CSize -> IO (Ptr Word8) memchr :: Ptr Word8 -> Word8 -> CSize -> IO (Ptr Word8) memchr p w s = c_memchr p (fromIntegral w) s foreign import ccall unsafe "string.h memcmp" c_memcmp :: Ptr Word8 -> Ptr Word8 -> CSize -> IO CInt memcmp :: Ptr Word8 -> Ptr Word8 -> Int -> IO CInt memcmp p q s = c_memcmp p q (fromIntegral s) foreign import ccall unsafe "string.h memcpy" c_memcpy :: Ptr Word8 -> Ptr Word8 -> CSize -> IO (Ptr Word8) memcpy :: Ptr Word8 -> Ptr Word8 -> Int -> IO () memcpy p q s = c_memcpy p q (fromIntegral s) >> return () {- foreign import ccall unsafe "string.h memmove" c_memmove :: Ptr Word8 -> Ptr Word8 -> CSize -> IO (Ptr Word8) memmove :: Ptr Word8 -> Ptr Word8 -> CSize -> IO () memmove p q s = do c_memmove p q s return () -} foreign import ccall unsafe "string.h memset" c_memset :: Ptr Word8 -> CInt -> CSize -> IO (Ptr Word8) memset :: Ptr Word8 -> Word8 -> CSize -> IO (Ptr Word8) memset p w s = c_memset p (fromIntegral w) s -- --------------------------------------------------------------------- -- -- Uses our C code -- foreign import ccall unsafe "static fpstring.h fps_reverse" c_reverse :: Ptr Word8 -> Ptr Word8 -> CULong -> IO () foreign import ccall unsafe "static fpstring.h fps_intersperse" c_intersperse :: Ptr Word8 -> Ptr Word8 -> CULong -> Word8 -> IO () foreign import ccall unsafe "static fpstring.h fps_maximum" c_maximum :: Ptr Word8 -> CULong -> IO Word8 foreign import ccall unsafe "static fpstring.h fps_minimum" c_minimum :: Ptr Word8 -> CULong -> IO Word8 foreign import ccall unsafe "static fpstring.h fps_count" c_count :: Ptr Word8 -> CULong -> Word8 -> IO CULong