{-# LANGUAGE CPP, BangPatterns #-} #if __GLASGOW_HASKELL__ >= 704 {-# LANGUAGE Trustworthy #-} #endif {-# OPTIONS_GHC -fno-warn-incomplete-patterns -fno-warn-orphans #-} -- | -- Module : Data.Vector.Storable.ByteString.Lazy -- Copyright : (c) Don Stewart 2006 -- (c) Duncan Coutts 2006 -- (c) Bas van Dijk 2011 -- License : BSD-style -- -- Maintainer : Bas van Dijk -- Stability : experimental -- Portability : portable -- -- A time and space-efficient implementation of lazy byte vectors -- using lists of packed 'Word8' arrays, suitable for high performance -- use, both in terms of large data quantities, or high speed -- requirements. Byte vectors are encoded as lazy lists of strict 'Word8' -- arrays of bytes. They provide a means to manipulate large byte vectors -- without requiring the entire vector be resident in memory. -- -- Some operations, such as concat, append, reverse and cons, have -- better complexity than their "Data.ByteString" equivalents, due to -- optimisations resulting from the list spine structure. And for other -- operations lazy ByteStrings are usually within a few percent of -- strict ones, but with better heap usage. For data larger than the -- available memory, or if you have tight memory constraints, this -- module will be the only option. The default chunk size is 64k, which -- should be good in most circumstances. For people with large L2 -- caches, you may want to increase this to fit your cache. -- -- This module is intended to be imported @qualified@, to avoid name -- clashes with "Prelude" functions. eg. -- -- > import qualified Data.Vector.Storable.ByteString.Lazy as B -- -- Original GHC implementation by Bryan O\'Sullivan. -- Rewritten to use 'Data.Array.Unboxed.UArray' by Simon Marlow. -- Rewritten to support slices and use 'Foreign.ForeignPtr.ForeignPtr' -- by David Roundy. -- Polished and extended by Don Stewart. -- Lazy variant by Duncan Coutts and Don Stewart. -- module Data.Vector.Storable.ByteString.Lazy ( -- * The @ByteString@ type ByteString, -- instances: Eq, Ord, Show, Read, Data, Typeable -- * Introducing and eliminating 'ByteString's empty, -- :: ByteString singleton, -- :: Word8 -> ByteString pack, -- :: [Word8] -> ByteString unpack, -- :: ByteString -> [Word8] fromChunks, -- :: [Strict.ByteString] -> ByteString toChunks, -- :: ByteString -> [Strict.ByteString] -- * Basic interface cons, -- :: Word8 -> ByteString -> ByteString cons', -- :: Word8 -> ByteString -> ByteString snoc, -- :: ByteString -> Word8 -> ByteString append, -- :: ByteString -> ByteString -> ByteString head, -- :: ByteString -> Word8 uncons, -- :: ByteString -> Maybe (Word8, ByteString) last, -- :: ByteString -> Word8 tail, -- :: ByteString -> ByteString init, -- :: ByteString -> ByteString null, -- :: ByteString -> Bool length, -- :: ByteString -> Int64 -- * Transforming ByteStrings map, -- :: (Word8 -> Word8) -> ByteString -> ByteString reverse, -- :: ByteString -> ByteString intersperse, -- :: Word8 -> ByteString -> ByteString intercalate, -- :: ByteString -> [ByteString] -> ByteString transpose, -- :: [ByteString] -> [ByteString] -- * Reducing 'ByteString's (folds) foldl, -- :: (a -> Word8 -> a) -> a -> ByteString -> a foldl', -- :: (a -> Word8 -> a) -> a -> ByteString -> a foldl1, -- :: (Word8 -> Word8 -> Word8) -> ByteString -> Word8 foldl1', -- :: (Word8 -> Word8 -> Word8) -> ByteString -> Word8 foldr, -- :: (Word8 -> a -> a) -> a -> ByteString -> a foldr1, -- :: (Word8 -> Word8 -> Word8) -> ByteString -> Word8 -- ** Special folds concat, -- :: [ByteString] -> ByteString concatMap, -- :: (Word8 -> ByteString) -> ByteString -> ByteString any, -- :: (Word8 -> Bool) -> ByteString -> Bool all, -- :: (Word8 -> Bool) -> ByteString -> Bool maximum, -- :: ByteString -> Word8 minimum, -- :: ByteString -> Word8 -- * Building ByteStrings -- ** Scans scanl, -- :: (Word8 -> Word8 -> Word8) -> Word8 -> ByteString -> ByteString -- scanl1, -- :: (Word8 -> Word8 -> Word8) -> ByteString -> ByteString -- scanr, -- :: (Word8 -> Word8 -> Word8) -> Word8 -> ByteString -> ByteString -- scanr1, -- :: (Word8 -> Word8 -> Word8) -> ByteString -> ByteString -- ** Accumulating maps mapAccumL, -- :: (acc -> Word8 -> (acc, Word8)) -> acc -> ByteString -> (acc, ByteString) mapAccumR, -- :: (acc -> Word8 -> (acc, Word8)) -> acc -> ByteString -> (acc, ByteString) -- ** Infinite ByteStrings repeat, -- :: Word8 -> ByteString replicate, -- :: Int64 -> Word8 -> ByteString cycle, -- :: ByteString -> ByteString iterate, -- :: (Word8 -> Word8) -> Word8 -> ByteString -- ** Unfolding ByteStrings unfoldr, -- :: (a -> Maybe (Word8, a)) -> a -> ByteString -- * Substrings -- ** Breaking strings take, -- :: Int64 -> ByteString -> ByteString drop, -- :: Int64 -> ByteString -> ByteString splitAt, -- :: Int64 -> ByteString -> (ByteString, ByteString) takeWhile, -- :: (Word8 -> Bool) -> ByteString -> ByteString dropWhile, -- :: (Word8 -> Bool) -> ByteString -> ByteString span, -- :: (Word8 -> Bool) -> ByteString -> (ByteString, ByteString) break, -- :: (Word8 -> Bool) -> ByteString -> (ByteString, ByteString) group, -- :: ByteString -> [ByteString] groupBy, -- :: (Word8 -> Word8 -> Bool) -> ByteString -> [ByteString] inits, -- :: ByteString -> [ByteString] tails, -- :: ByteString -> [ByteString] -- ** Breaking into many substrings split, -- :: Word8 -> ByteString -> [ByteString] splitWith, -- :: (Word8 -> Bool) -> ByteString -> [ByteString] -- * Predicates isPrefixOf, -- :: ByteString -> ByteString -> Bool isSuffixOf, -- :: ByteString -> ByteString -> Bool -- isInfixOf, -- :: ByteString -> ByteString -> Bool -- ** Search for arbitrary substrings -- isSubstringOf, -- :: ByteString -> ByteString -> Bool -- findSubstring, -- :: ByteString -> ByteString -> Maybe Int -- findSubstrings, -- :: ByteString -> ByteString -> [Int] -- * Searching ByteStrings -- ** Searching by equality elem, -- :: Word8 -> ByteString -> Bool notElem, -- :: Word8 -> ByteString -> Bool -- ** Searching with a predicate find, -- :: (Word8 -> Bool) -> ByteString -> Maybe Word8 filter, -- :: (Word8 -> Bool) -> ByteString -> ByteString partition, -- :: (Word8 -> Bool) -> ByteString -> (ByteString, ByteString) -- * Indexing ByteStrings index, -- :: ByteString -> Int64 -> Word8 elemIndex, -- :: Word8 -> ByteString -> Maybe Int64 elemIndices, -- :: Word8 -> ByteString -> [Int64] findIndex, -- :: (Word8 -> Bool) -> ByteString -> Maybe Int64 findIndices, -- :: (Word8 -> Bool) -> ByteString -> [Int64] count, -- :: Word8 -> ByteString -> Int64 -- * Zipping and unzipping ByteStrings zip, -- :: ByteString -> ByteString -> [(Word8,Word8)] zipWith, -- :: (Word8 -> Word8 -> c) -> ByteString -> ByteString -> [c] unzip, -- :: [(Word8,Word8)] -> (ByteString,ByteString) -- * Ordered ByteStrings -- sort, -- :: ByteString -> ByteString -- * Low level conversions -- ** Copying ByteStrings copy, -- :: ByteString -> ByteString -- defrag, -- :: ByteString -> ByteString -- * I\/O with 'ByteString's -- ** Standard input and output getContents, -- :: IO ByteString putStr, -- :: ByteString -> IO () putStrLn, -- :: ByteString -> IO () interact, -- :: (ByteString -> ByteString) -> IO () -- ** Files readFile, -- :: FilePath -> IO ByteString writeFile, -- :: FilePath -> ByteString -> IO () appendFile, -- :: FilePath -> ByteString -> IO () -- ** I\/O with Handles hGetContents, -- :: Handle -> IO ByteString hGet, -- :: Handle -> Int -> IO ByteString hGetNonBlocking, -- :: Handle -> Int -> IO ByteString hPut, -- :: Handle -> ByteString -> IO () hPutNonBlocking, -- :: Handle -> ByteString -> IO ByteString hPutStr, -- :: Handle -> ByteString -> IO () ) where import Prelude hiding (reverse,head,tail,last,init,null,length,map,lines,foldl,foldr,unlines ,concat,any,take,drop,splitAt,takeWhile,dropWhile,span,break,elem,filter,maximum ,minimum,all,concatMap,foldl1,foldr1,scanl, scanl1, scanr, scanr1 ,repeat, cycle, interact, iterate,readFile,writeFile,appendFile,replicate ,getContents,getLine,putStr,putStrLn ,zip,zipWith,unzip,notElem) import qualified Data.List as L -- L for list/lazy import qualified Data.Vector.Storable.ByteString as P (ByteString) -- type name only import qualified Data.Vector.Storable.ByteString as S -- S for strict (hmm...) import qualified Data.Vector.Storable.ByteString.Internal as S import qualified Data.Vector.Storable.ByteString.Unsafe as S import Data.Vector.Storable.ByteString.Lazy.Internal import Data.Monoid (Monoid(..)) import Data.Word (Word8) import Data.Int (Int64) import System.IO (Handle,stdin,stdout,openBinaryFile,IOMode(..) ,hClose) import System.IO.Error (mkIOError, illegalOperationErrorType) import System.IO.Unsafe import Control.Exception (bracket) import Foreign.ForeignPtr (withForeignPtr) import Foreign.Ptr import Foreign.Storable -- from vector: import qualified Data.Vector.Storable as VS ( unsafeToForeignPtr0, unsafeToForeignPtr0 ) -- ----------------------------------------------------------------------------- instance Eq ByteString where (==) = eq instance Ord ByteString where compare = cmp instance Monoid ByteString where mempty = empty mappend = append mconcat = concat eq :: ByteString -> ByteString -> Bool eq Empty Empty = True eq Empty _ = False eq _ Empty = False eq (Chunk a as) (Chunk b bs) = case compare (S.length a) (S.length b) of LT -> a == (S.take (S.length a) b) && eq as (Chunk (S.drop (S.length a) b) bs) EQ -> a == b && eq as bs GT -> (S.take (S.length b) a) == b && eq (Chunk (S.drop (S.length b) a) as) bs cmp :: ByteString -> ByteString -> Ordering cmp Empty Empty = EQ cmp Empty _ = LT cmp _ Empty = GT cmp (Chunk a as) (Chunk b bs) = case compare (S.length a) (S.length b) of LT -> case compare a (S.take (S.length a) b) of EQ -> cmp as (Chunk (S.drop (S.length a) b) bs) result -> result EQ -> case compare a b of EQ -> cmp as bs result -> result GT -> case compare (S.take (S.length b) a) b of EQ -> cmp (Chunk (S.drop (S.length b) a) as) bs result -> result -- ----------------------------------------------------------------------------- -- Introducing and eliminating 'ByteString's -- | /O(1)/ The empty 'ByteString' empty :: ByteString empty = Empty {-# INLINE empty #-} -- | /O(1)/ Convert a 'Word8' into a 'ByteString' singleton :: Word8 -> ByteString singleton w = Chunk (S.singleton w) Empty {-# INLINE singleton #-} -- | /O(n)/ Convert a '[Word8]' into a 'ByteString'. pack :: [Word8] -> ByteString pack ws = L.foldr (Chunk . S.pack) Empty (chunks defaultChunkSize ws) where chunks :: Int -> [a] -> [[a]] chunks _ [] = [] chunks size xs = case L.splitAt size xs of (xs', xs'') -> xs' : chunks size xs'' -- | /O(n)/ Converts a 'ByteString' to a '[Word8]'. unpack :: ByteString -> [Word8] unpack cs = L.concatMap S.unpack (toChunks cs) --TODO: we can do better here by integrating the concat with the unpack -- | /O(c)/ Convert a list of strict 'ByteString' into a lazy 'ByteString' fromChunks :: [P.ByteString] -> ByteString fromChunks cs = L.foldr chunk Empty cs -- | /O(n)/ Convert a lazy 'ByteString' into a list of strict 'ByteString' toChunks :: ByteString -> [P.ByteString] toChunks cs = foldrChunks (:) [] cs ------------------------------------------------------------------------ {- -- | /O(n)/ Convert a '[a]' into a 'ByteString' using some -- conversion function packWith :: (a -> Word8) -> [a] -> ByteString packWith k str = LPS $ L.map (P.packWith k) (chunk defaultChunkSize str) {-# INLINE packWith #-} {-# SPECIALIZE packWith :: (Char -> Word8) -> [Char] -> ByteString #-} -- | /O(n)/ Converts a 'ByteString' to a '[a]', using a conversion function. unpackWith :: (Word8 -> a) -> ByteString -> [a] unpackWith k (LPS ss) = L.concatMap (S.unpackWith k) ss {-# INLINE unpackWith #-} {-# SPECIALIZE unpackWith :: (Word8 -> Char) -> ByteString -> [Char] #-} -} -- --------------------------------------------------------------------- -- Basic interface -- | /O(1)/ Test whether a ByteString is empty. null :: ByteString -> Bool null Empty = True null _ = False {-# INLINE null #-} -- | /O(n\/c)/ 'length' returns the length of a ByteString as an 'Int64' length :: ByteString -> Int64 length cs = foldlChunks (\n c -> n + fromIntegral (S.length c)) 0 cs {-# INLINE length #-} -- | /O(1)/ 'cons' is analogous to '(:)' for lists. -- cons :: Word8 -> ByteString -> ByteString cons c cs = Chunk (S.singleton c) cs {-# INLINE cons #-} -- | /O(1)/ Unlike 'cons', 'cons\'' is -- strict in the ByteString that we are consing onto. More precisely, it forces -- the head and the first chunk. It does this because, for space efficiency, it -- may coalesce the new byte onto the first \'chunk\' rather than starting a -- new \'chunk\'. -- -- So that means you can't use a lazy recursive contruction like this: -- -- > let xs = cons\' c xs in xs -- -- You can however use 'cons', as well as 'repeat' and 'cycle', to build -- infinite lazy ByteStrings. -- cons' :: Word8 -> ByteString -> ByteString cons' w (Chunk c cs) | S.length c < 16 = Chunk (S.cons w c) cs cons' w cs = Chunk (S.singleton w) cs {-# INLINE cons' #-} -- | /O(n\/c)/ Append a byte to the end of a 'ByteString' snoc :: ByteString -> Word8 -> ByteString snoc cs w = foldrChunks Chunk (singleton w) cs {-# INLINE snoc #-} -- | /O(1)/ Extract the first element of a ByteString, which must be non-empty. head :: ByteString -> Word8 head Empty = errorEmptyList "head" head (Chunk c _) = S.unsafeHead c {-# INLINE head #-} -- | /O(1)/ Extract the head and tail of a ByteString, returning Nothing -- if it is empty. uncons :: ByteString -> Maybe (Word8, ByteString) uncons Empty = Nothing uncons (Chunk c cs) = Just (S.unsafeHead c, if S.length c == 1 then cs else Chunk (S.unsafeTail c) cs) {-# INLINE uncons #-} -- | /O(1)/ Extract the elements after the head of a ByteString, which must be -- non-empty. tail :: ByteString -> ByteString tail Empty = errorEmptyList "tail" tail (Chunk c cs) | S.length c == 1 = cs | otherwise = Chunk (S.unsafeTail c) cs {-# INLINE tail #-} -- | /O(n\/c)/ Extract the last element of a ByteString, which must be finite -- and non-empty. last :: ByteString -> Word8 last Empty = errorEmptyList "last" last (Chunk c0 cs0) = go c0 cs0 where go c Empty = S.last c go _ (Chunk c cs) = go c cs -- XXX Don't inline this. Something breaks with 6.8.2 (haven't investigated yet) -- | /O(n\/c)/ Return all the elements of a 'ByteString' except the last one. init :: ByteString -> ByteString init Empty = errorEmptyList "init" init (Chunk c0 cs0) = go c0 cs0 where go c Empty | S.length c == 1 = Empty | otherwise = Chunk (S.init c) Empty go c (Chunk c' cs) = Chunk c (go c' cs) -- | /O(n\/c)/ Append two ByteStrings append :: ByteString -> ByteString -> ByteString append xs ys = foldrChunks Chunk ys xs {-# INLINE append #-} -- --------------------------------------------------------------------- -- Transformations -- | /O(n)/ 'map' @f xs@ is the ByteString obtained by applying @f@ to each -- element of @xs@. map :: (Word8 -> Word8) -> ByteString -> ByteString map f s = go s where go Empty = Empty go (Chunk x xs) = Chunk y ys where y = S.map f x ys = go xs {-# INLINE map #-} -- | /O(n)/ 'reverse' @xs@ returns the elements of @xs@ in reverse order. reverse :: ByteString -> ByteString reverse cs0 = rev Empty cs0 where rev a Empty = a rev a (Chunk c cs) = rev (Chunk (S.reverse c) a) cs {-# INLINE reverse #-} -- | The 'intersperse' function takes a 'Word8' and a 'ByteString' and -- \`intersperses\' that byte between the elements of the 'ByteString'. -- It is analogous to the intersperse function on Lists. intersperse :: Word8 -> ByteString -> ByteString intersperse _ Empty = Empty intersperse w (Chunk c cs) = Chunk (S.intersperse w c) (foldrChunks (Chunk . intersperse') Empty cs) where intersperse' :: P.ByteString -> P.ByteString intersperse' v = S.unsafeCreate (2*l) $ \p' -> withForeignPtr fp $ \p -> do poke p' w S.c_intersperse (p' `plusPtr` 1) p (fromIntegral l) w where (fp, l) = VS.unsafeToForeignPtr0 v -- | The 'transpose' function transposes the rows and columns of its -- 'ByteString' argument. transpose :: [ByteString] -> [ByteString] transpose css = L.map (\ss -> Chunk (S.pack ss) Empty) (L.transpose (L.map unpack css)) --TODO: make this fast -- --------------------------------------------------------------------- -- Reducing 'ByteString's -- | 'foldl', applied to a binary operator, a starting value (typically -- the left-identity of the operator), and a ByteString, reduces the -- ByteString using the binary operator, from left to right. foldl :: (a -> Word8 -> a) -> a -> ByteString -> a foldl f z = go z where go a Empty = a go a (Chunk c cs) = go (S.foldl f a c) cs {-# INLINE foldl #-} -- | 'foldl\'' is like 'foldl', but strict in the accumulator. foldl' :: (a -> Word8 -> a) -> a -> ByteString -> a foldl' f z = go z where go a _ | a `seq` False = undefined go a Empty = a go a (Chunk c cs) = go (S.foldl f a c) cs {-# INLINE foldl' #-} -- | 'foldr', applied to a binary operator, a starting value -- (typically the right-identity of the operator), and a ByteString, -- reduces the ByteString using the binary operator, from right to left. foldr :: (Word8 -> a -> a) -> a -> ByteString -> a foldr k z cs = foldrChunks (flip (S.foldr k)) z cs {-# INLINE foldr #-} -- | 'foldl1' is a variant of 'foldl' that has no starting value -- argument, and thus must be applied to non-empty 'ByteStrings'. -- This function is subject to array fusion. foldl1 :: (Word8 -> Word8 -> Word8) -> ByteString -> Word8 foldl1 _ Empty = errorEmptyList "foldl1" foldl1 f (Chunk c cs) = foldl f (S.unsafeHead c) (Chunk (S.unsafeTail c) cs) -- | 'foldl1\'' is like 'foldl1', but strict in the accumulator. foldl1' :: (Word8 -> Word8 -> Word8) -> ByteString -> Word8 foldl1' _ Empty = errorEmptyList "foldl1'" foldl1' f (Chunk c cs) = foldl' f (S.unsafeHead c) (Chunk (S.unsafeTail c) cs) -- | 'foldr1' is a variant of 'foldr' that has no starting value argument, -- and thus must be applied to non-empty 'ByteString's foldr1 :: (Word8 -> Word8 -> Word8) -> ByteString -> Word8 foldr1 _ Empty = errorEmptyList "foldr1" foldr1 f (Chunk c0 cs0) = go c0 cs0 where go c Empty = S.foldr1 f c go c (Chunk c' cs) = S.foldr f (go c' cs) c -- --------------------------------------------------------------------- -- Special folds -- | /O(n)/ Concatenate a list of ByteStrings. concat :: [ByteString] -> ByteString concat css0 = to css0 where go Empty css = to css go (Chunk c cs) css = Chunk c (go cs css) to [] = Empty to (cs:css) = go cs css -- | Map a function over a 'ByteString' and concatenate the results concatMap :: (Word8 -> ByteString) -> ByteString -> ByteString concatMap _ Empty = Empty concatMap f (Chunk c0 cs0) = to c0 cs0 where go :: ByteString -> P.ByteString -> ByteString -> ByteString go Empty c' cs' = to c' cs' go (Chunk c cs) c' cs' = Chunk c (go cs c' cs') to :: P.ByteString -> ByteString -> ByteString to c cs | S.null c = case cs of Empty -> Empty (Chunk c' cs') -> to c' cs' | otherwise = go (f (S.unsafeHead c)) (S.unsafeTail c) cs -- | /O(n)/ Applied to a predicate and a ByteString, 'any' determines if -- any element of the 'ByteString' satisfies the predicate. any :: (Word8 -> Bool) -> ByteString -> Bool any f cs = foldrChunks (\c rest -> S.any f c || rest) False cs {-# INLINE any #-} -- todo fuse -- | /O(n)/ Applied to a predicate and a 'ByteString', 'all' determines -- if all elements of the 'ByteString' satisfy the predicate. all :: (Word8 -> Bool) -> ByteString -> Bool all f cs = foldrChunks (\c rest -> S.all f c && rest) True cs {-# INLINE all #-} -- todo fuse -- | /O(n)/ 'maximum' returns the maximum value from a 'ByteString' maximum :: ByteString -> Word8 maximum Empty = errorEmptyList "maximum" maximum (Chunk c cs) = foldlChunks (\n c' -> n `max` S.maximum c') (S.maximum c) cs {-# INLINE maximum #-} -- | /O(n)/ 'minimum' returns the minimum value from a 'ByteString' minimum :: ByteString -> Word8 minimum Empty = errorEmptyList "minimum" minimum (Chunk c cs) = foldlChunks (\n c' -> n `min` S.minimum c') (S.minimum c) cs {-# INLINE minimum #-} -- | The 'mapAccumL' function behaves like a combination of 'map' and -- 'foldl'; it applies a function to each element of a ByteString, -- passing an accumulating parameter from left to right, and returning a -- final value of this accumulator together with the new ByteString. mapAccumL :: (acc -> Word8 -> (acc, Word8)) -> acc -> ByteString -> (acc, ByteString) mapAccumL f s0 cs0 = go s0 cs0 where go s Empty = (s, Empty) go s (Chunk c cs) = (s'', Chunk c' cs') where (s', c') = S.mapAccumL f s c (s'', cs') = go s' cs -- | The 'mapAccumR' function behaves like a combination of 'map' and -- 'foldr'; it applies a function to each element of a ByteString, -- passing an accumulating parameter from right to left, and returning a -- final value of this accumulator together with the new ByteString. mapAccumR :: (acc -> Word8 -> (acc, Word8)) -> acc -> ByteString -> (acc, ByteString) mapAccumR f s0 cs0 = go s0 cs0 where go s Empty = (s, Empty) go s (Chunk c cs) = (s'', Chunk c' cs') where (s'', c') = S.mapAccumR f s' c (s', cs') = go s cs -- --------------------------------------------------------------------- -- Building ByteStrings -- | 'scanl' is similar to 'foldl', but returns a list of successive -- reduced values from the left. This function will fuse. -- -- > scanl f z [x1, x2, ...] == [z, z `f` x1, (z `f` x1) `f` x2, ...] -- -- Note that -- -- > last (scanl f z xs) == foldl f z xs. scanl :: (Word8 -> Word8 -> Word8) -> Word8 -> ByteString -> ByteString scanl f z = snd . foldl k (z,singleton z) where k (c,acc) a = let n = f c a in (n, acc `snoc` n) {-# INLINE scanl #-} -- --------------------------------------------------------------------- -- Unfolds and replicates -- | @'iterate' f x@ returns an infinite ByteString of repeated applications -- of @f@ to @x@: -- -- > iterate f x == [x, f x, f (f x), ...] -- iterate :: (Word8 -> Word8) -> Word8 -> ByteString iterate f = unfoldr (\x -> case f x of x' -> x' `seq` Just (x', x')) -- | @'repeat' x@ is an infinite ByteString, with @x@ the value of every -- element. -- repeat :: Word8 -> ByteString repeat w = cs where cs = Chunk (S.replicate smallChunkSize w) cs -- | /O(n)/ @'replicate' n x@ is a ByteString of length @n@ with @x@ -- the value of every element. -- replicate :: Int64 -> Word8 -> ByteString replicate n w | n <= 0 = Empty | n < fromIntegral smallChunkSize = Chunk (S.replicate (fromIntegral n) w) Empty | r == 0 = cs -- preserve invariant | otherwise = Chunk (S.unsafeTake (fromIntegral r) c) cs where c = S.replicate smallChunkSize w cs = nChunks q (q, r) = quotRem n (fromIntegral smallChunkSize) nChunks 0 = Empty nChunks m = Chunk c (nChunks (m-1)) -- | 'cycle' ties a finite ByteString into a circular one, or equivalently, -- the infinite repetition of the original ByteString. -- cycle :: ByteString -> ByteString cycle Empty = errorEmptyList "cycle" cycle cs = cs' where cs' = foldrChunks Chunk cs' cs -- | /O(n)/ The 'unfoldr' function is analogous to the List \'unfoldr\'. -- 'unfoldr' builds a ByteString from a seed value. The function takes -- the element and returns 'Nothing' if it is done producing the -- ByteString or returns 'Just' @(a,b)@, in which case, @a@ is a -- prepending to the ByteString and @b@ is used as the next element in a -- recursive call. unfoldr :: (a -> Maybe (Word8, a)) -> a -> ByteString unfoldr f s0 = unfoldChunk 32 s0 where unfoldChunk n s = case S.unfoldrN n f s of (c, Nothing) | S.null c -> Empty | otherwise -> Chunk c Empty (c, Just s') -> Chunk c (unfoldChunk (n*2) s') -- --------------------------------------------------------------------- -- Substrings -- | /O(n\/c)/ 'take' @n@, applied to a ByteString @xs@, returns the prefix -- of @xs@ of length @n@, or @xs@ itself if @n > 'length' xs@. take :: Int64 -> ByteString -> ByteString take i _ | i <= 0 = Empty take i cs0 = take' i cs0 where take' 0 _ = Empty take' _ Empty = Empty take' n (Chunk c cs) = if n < fromIntegral (S.length c) then Chunk (S.take (fromIntegral n) c) Empty else Chunk c (take' (n - fromIntegral (S.length c)) cs) -- | /O(n\/c)/ 'drop' @n xs@ returns the suffix of @xs@ after the first @n@ -- elements, or @[]@ if @n > 'length' xs@. drop :: Int64 -> ByteString -> ByteString drop i p | i <= 0 = p drop i cs0 = drop' i cs0 where drop' 0 cs = cs drop' _ Empty = Empty drop' n (Chunk c cs) = if n < fromIntegral (S.length c) then Chunk (S.drop (fromIntegral n) c) cs else drop' (n - fromIntegral (S.length c)) cs -- | /O(n\/c)/ 'splitAt' @n xs@ is equivalent to @('take' n xs, 'drop' n xs)@. splitAt :: Int64 -> ByteString -> (ByteString, ByteString) splitAt i cs0 | i <= 0 = (Empty, cs0) splitAt i cs0 = splitAt' i cs0 where splitAt' 0 cs = (Empty, cs) splitAt' _ Empty = (Empty, Empty) splitAt' n (Chunk c cs) = if n < fromIntegral (S.length c) then (Chunk (S.take (fromIntegral n) c) Empty ,Chunk (S.drop (fromIntegral n) c) cs) else let (cs', cs'') = splitAt' (n - fromIntegral (S.length c)) cs in (Chunk c cs', cs'') -- | 'takeWhile', applied to a predicate @p@ and a ByteString @xs@, -- returns the longest prefix (possibly empty) of @xs@ of elements that -- satisfy @p@. takeWhile :: (Word8 -> Bool) -> ByteString -> ByteString takeWhile f cs0 = takeWhile' cs0 where takeWhile' Empty = Empty takeWhile' (Chunk c cs) = case findIndexOrEnd (not . f) c of 0 -> Empty n | n < S.length c -> Chunk (S.take n c) Empty | otherwise -> Chunk c (takeWhile' cs) -- | 'dropWhile' @p xs@ returns the suffix remaining after 'takeWhile' @p xs@. dropWhile :: (Word8 -> Bool) -> ByteString -> ByteString dropWhile f cs0 = dropWhile' cs0 where dropWhile' Empty = Empty dropWhile' (Chunk c cs) = case findIndexOrEnd (not . f) c of n | n < S.length c -> Chunk (S.drop n c) cs | otherwise -> dropWhile' cs -- | 'break' @p@ is equivalent to @'span' ('not' . p)@. break :: (Word8 -> Bool) -> ByteString -> (ByteString, ByteString) break f cs0 = break' cs0 where break' Empty = (Empty, Empty) break' (Chunk c cs) = case findIndexOrEnd f c of 0 -> (Empty, Chunk c cs) n | n < S.length c -> (Chunk (S.take n c) Empty ,Chunk (S.drop n c) cs) | otherwise -> let (cs', cs'') = break' cs in (Chunk c cs', cs'') -- -- TODO -- -- Add rules -- {- -- | 'breakByte' breaks its ByteString argument at the first occurence -- of the specified byte. It is more efficient than 'break' as it is -- implemented with @memchr(3)@. I.e. -- -- > break (=='c') "abcd" == breakByte 'c' "abcd" -- breakByte :: Word8 -> ByteString -> (ByteString, ByteString) breakByte c (LPS ps) = case (breakByte' ps) of (a,b) -> (LPS a, LPS b) where breakByte' [] = ([], []) breakByte' (x:xs) = case P.elemIndex c x of Just 0 -> ([], x : xs) Just n -> (P.take n x : [], P.drop n x : xs) Nothing -> let (xs', xs'') = breakByte' xs in (x : xs', xs'') -- | 'spanByte' breaks its ByteString argument at the first -- occurence of a byte other than its argument. It is more efficient -- than 'span (==)' -- -- > span (=='c') "abcd" == spanByte 'c' "abcd" -- spanByte :: Word8 -> ByteString -> (ByteString, ByteString) spanByte c (LPS ps) = case (spanByte' ps) of (a,b) -> (LPS a, LPS b) where spanByte' [] = ([], []) spanByte' (x:xs) = case P.spanByte c x of (x', x'') | P.null x' -> ([], x : xs) | P.null x'' -> let (xs', xs'') = spanByte' xs in (x : xs', xs'') | otherwise -> (x' : [], x'' : xs) -} -- | 'span' @p xs@ breaks the ByteString into two segments. It is -- equivalent to @('takeWhile' p xs, 'dropWhile' p xs)@ span :: (Word8 -> Bool) -> ByteString -> (ByteString, ByteString) span p = break (not . p) -- | /O(n)/ Splits a 'ByteString' into components delimited by -- separators, where the predicate returns True for a separator element. -- The resulting components do not contain the separators. Two adjacent -- separators result in an empty component in the output. eg. -- -- > splitWith (=='a') "aabbaca" == ["","","bb","c",""] -- > splitWith (=='a') [] == [] -- splitWith :: (Word8 -> Bool) -> ByteString -> [ByteString] splitWith _ Empty = [] splitWith p (Chunk c0 cs0) = comb [] (S.splitWith p c0) cs0 where comb :: [P.ByteString] -> [P.ByteString] -> ByteString -> [ByteString] comb acc (s:[]) Empty = revChunks (s:acc) : [] comb acc (s:[]) (Chunk c cs) = comb (s:acc) (S.splitWith p c) cs comb acc (s:ss) cs = revChunks (s:acc) : comb [] ss cs {-# INLINE splitWith #-} -- | /O(n)/ Break a 'ByteString' into pieces separated by the byte -- argument, consuming the delimiter. I.e. -- -- > split '\n' "a\nb\nd\ne" == ["a","b","d","e"] -- > split 'a' "aXaXaXa" == ["","X","X","X",""] -- > split 'x' "x" == ["",""] -- -- and -- -- > intercalate [c] . split c == id -- > split == splitWith . (==) -- -- As for all splitting functions in this library, this function does -- not copy the substrings, it just constructs new 'ByteStrings' that -- are slices of the original. -- split :: Word8 -> ByteString -> [ByteString] split _ Empty = [] split w (Chunk c0 cs0) = comb [] (S.split w c0) cs0 where comb :: [P.ByteString] -> [P.ByteString] -> ByteString -> [ByteString] comb acc (s:[]) Empty = revChunks (s:acc) : [] comb acc (s:[]) (Chunk c cs) = comb (s:acc) (S.split w c) cs comb acc (s:ss) cs = revChunks (s:acc) : comb [] ss cs {-# INLINE split #-} {- -- | Like 'splitWith', except that sequences of adjacent separators are -- treated as a single separator. eg. -- -- > tokens (=='a') "aabbaca" == ["bb","c"] -- tokens :: (Word8 -> Bool) -> ByteString -> [ByteString] tokens f = L.filter (not.null) . splitWith f -} -- | The 'group' function takes a ByteString and returns a list of -- ByteStrings such that the concatenation of the result is equal to the -- argument. Moreover, each sublist in the result contains only equal -- elements. For example, -- -- > group "Mississippi" = ["M","i","ss","i","ss","i","pp","i"] -- -- It is a special case of 'groupBy', which allows the programmer to -- supply their own equality test. group :: ByteString -> [ByteString] group Empty = [] group (Chunk c0 cs0) = group' [] (S.group c0) cs0 where group' :: [P.ByteString] -> [P.ByteString] -> ByteString -> [ByteString] group' acc@(s':_) ss@(s:_) cs | S.unsafeHead s' /= S.unsafeHead s = revNonEmptyChunks acc : group' [] ss cs group' acc (s:[]) Empty = revNonEmptyChunks (s:acc) : [] group' acc (s:[]) (Chunk c cs) = group' (s:acc) (S.group c) cs group' acc (s:ss) cs = revNonEmptyChunks (s:acc) : group' [] ss cs {- TODO: check if something like this might be faster group :: ByteString -> [ByteString] group xs | null xs = [] | otherwise = ys : group zs where (ys, zs) = spanByte (unsafeHead xs) xs -} -- | The 'groupBy' function is the non-overloaded version of 'group'. -- groupBy :: (Word8 -> Word8 -> Bool) -> ByteString -> [ByteString] groupBy _ Empty = [] groupBy k (Chunk c0 cs0) = groupBy' [] 0 (S.groupBy k c0) cs0 where groupBy' :: [P.ByteString] -> Word8 -> [P.ByteString] -> ByteString -> [ByteString] groupBy' acc@(_:_) c ss@(s:_) cs | not (c `k` S.unsafeHead s) = revNonEmptyChunks acc : groupBy' [] 0 ss cs groupBy' acc _ (s:[]) Empty = revNonEmptyChunks (s : acc) : [] groupBy' acc w (s:[]) (Chunk c cs) = groupBy' (s:acc) w' (S.groupBy k c) cs where w' | L.null acc = S.unsafeHead s | otherwise = w groupBy' acc _ (s:ss) cs = revNonEmptyChunks (s : acc) : groupBy' [] 0 ss cs {- TODO: check if something like this might be faster groupBy :: (Word8 -> Word8 -> Bool) -> ByteString -> [ByteString] groupBy k xs | null xs = [] | otherwise = take n xs : groupBy k (drop n xs) where n = 1 + findIndexOrEnd (not . k (head xs)) (tail xs) -} -- | /O(n)/ The 'intercalate' function takes a 'ByteString' and a list of -- 'ByteString's and concatenates the list after interspersing the first -- argument between each element of the list. intercalate :: ByteString -> [ByteString] -> ByteString intercalate s = concat . (L.intersperse s) -- --------------------------------------------------------------------- -- Indexing ByteStrings -- | /O(c)/ 'ByteString' index (subscript) operator, starting from 0. index :: ByteString -> Int64 -> Word8 index _ i | i < 0 = moduleError "index" ("negative index: " ++ show i) index cs0 i = index' cs0 i where index' Empty n = moduleError "index" ("index too large: " ++ show n) index' (Chunk c cs) n | n >= fromIntegral (S.length c) = index' cs (n - fromIntegral (S.length c)) | otherwise = S.unsafeIndex c (fromIntegral n) -- | /O(n)/ The 'elemIndex' function returns the index of the first -- element in the given 'ByteString' which is equal to the query -- element, or 'Nothing' if there is no such element. -- This implementation uses memchr(3). elemIndex :: Word8 -> ByteString -> Maybe Int64 elemIndex w cs0 = elemIndex' 0 cs0 where elemIndex' _ Empty = Nothing elemIndex' n (Chunk c cs) = case S.elemIndex w c of Nothing -> elemIndex' (n + fromIntegral (S.length c)) cs Just i -> Just (n + fromIntegral i) {- -- | /O(n)/ The 'elemIndexEnd' function returns the last index of the -- element in the given 'ByteString' which is equal to the query -- element, or 'Nothing' if there is no such element. The following -- holds: -- -- > elemIndexEnd c xs == -- > (-) (length xs - 1) `fmap` elemIndex c (reverse xs) -- elemIndexEnd :: Word8 -> ByteString -> Maybe Int elemIndexEnd ch (PS x s l) = inlinePerformIO $ withForeignPtr x $ \p -> go (p `plusPtr` s) (l-1) where go !p !i | i < 0 = return Nothing | otherwise = do ch' <- peekByteOff p i if ch == ch' then return $ Just i else go p (i-1) -} -- | /O(n)/ The 'elemIndices' function extends 'elemIndex', by returning -- the indices of all elements equal to the query element, in ascending order. -- This implementation uses memchr(3). elemIndices :: Word8 -> ByteString -> [Int64] elemIndices w cs0 = elemIndices' 0 cs0 where elemIndices' _ Empty = [] elemIndices' n (Chunk c cs) = L.map ((+n).fromIntegral) (S.elemIndices w c) ++ elemIndices' (n + fromIntegral (S.length c)) cs -- | count returns the number of times its argument appears in the ByteString -- -- > count = length . elemIndices -- -- But more efficiently than using length on the intermediate list. count :: Word8 -> ByteString -> Int64 count w cs = foldlChunks (\n c -> n + fromIntegral (S.count w c)) 0 cs -- | The 'findIndex' function takes a predicate and a 'ByteString' and -- returns the index of the first element in the ByteString -- satisfying the predicate. findIndex :: (Word8 -> Bool) -> ByteString -> Maybe Int64 findIndex k cs0 = findIndex' 0 cs0 where findIndex' _ Empty = Nothing findIndex' n (Chunk c cs) = case S.findIndex k c of Nothing -> findIndex' (n + fromIntegral (S.length c)) cs Just i -> Just (n + fromIntegral i) {-# INLINE findIndex #-} -- | /O(n)/ The 'find' function takes a predicate and a ByteString, -- and returns the first element in matching the predicate, or 'Nothing' -- if there is no such element. -- -- > find f p = case findIndex f p of Just n -> Just (p ! n) ; _ -> Nothing -- find :: (Word8 -> Bool) -> ByteString -> Maybe Word8 find f cs0 = find' cs0 where find' Empty = Nothing find' (Chunk c cs) = case S.find f c of Nothing -> find' cs Just w -> Just w {-# INLINE find #-} -- | The 'findIndices' function extends 'findIndex', by returning the -- indices of all elements satisfying the predicate, in ascending order. findIndices :: (Word8 -> Bool) -> ByteString -> [Int64] findIndices k cs0 = findIndices' 0 cs0 where findIndices' _ Empty = [] findIndices' n (Chunk c cs) = L.map ((+n).fromIntegral) (S.findIndices k c) ++ findIndices' (n + fromIntegral (S.length c)) cs -- --------------------------------------------------------------------- -- Searching ByteStrings -- | /O(n)/ 'elem' is the 'ByteString' membership predicate. elem :: Word8 -> ByteString -> Bool elem w cs = case elemIndex w cs of Nothing -> False ; _ -> True -- | /O(n)/ 'notElem' is the inverse of 'elem' notElem :: Word8 -> ByteString -> Bool notElem w cs = not (elem w cs) -- | /O(n)/ 'filter', applied to a predicate and a ByteString, -- returns a ByteString containing those characters that satisfy the -- predicate. filter :: (Word8 -> Bool) -> ByteString -> ByteString filter p s = go s where go Empty = Empty go (Chunk x xs) = chunk (S.filter p x) (go xs) {-# INLINE filter #-} {- -- | /O(n)/ and /O(n\/c) space/ A first order equivalent of /filter . -- (==)/, for the common case of filtering a single byte. It is more -- efficient to use /filterByte/ in this case. -- -- > filterByte == filter . (==) -- -- filterByte is around 10x faster, and uses much less space, than its -- filter equivalent filterByte :: Word8 -> ByteString -> ByteString filterByte w ps = replicate (count w ps) w {-# INLINE filterByte #-} {-# RULES "ByteString specialise filter (== x)" forall x. filter ((==) x) = filterByte x "ByteString specialise filter (== x)" forall x. filter (== x) = filterByte x #-} -} {- -- | /O(n)/ A first order equivalent of /filter . (\/=)/, for the common -- case of filtering a single byte out of a list. It is more efficient -- to use /filterNotByte/ in this case. -- -- > filterNotByte == filter . (/=) -- -- filterNotByte is around 2x faster than its filter equivalent. filterNotByte :: Word8 -> ByteString -> ByteString filterNotByte w (LPS xs) = LPS (filterMap (P.filterNotByte w) xs) -} -- | /O(n)/ The 'partition' function takes a predicate a ByteString and returns -- the pair of ByteStrings with elements which do and do not satisfy the -- predicate, respectively; i.e., -- -- > partition p bs == (filter p xs, filter (not . p) xs) -- partition :: (Word8 -> Bool) -> ByteString -> (ByteString, ByteString) partition f p = (filter f p, filter (not . f) p) --TODO: use a better implementation -- --------------------------------------------------------------------- -- Searching for substrings -- | /O(n)/ The 'isPrefixOf' function takes two ByteStrings and returns 'True' -- iff the first is a prefix of the second. isPrefixOf :: ByteString -> ByteString -> Bool isPrefixOf Empty _ = True isPrefixOf _ Empty = False isPrefixOf (Chunk x xs) (Chunk y ys) | S.length x == S.length y = x == y && isPrefixOf xs ys | S.length x < S.length y = x == yh && isPrefixOf xs (Chunk yt ys) | otherwise = xh == y && isPrefixOf (Chunk xt xs) ys where (xh,xt) = S.splitAt (S.length y) x (yh,yt) = S.splitAt (S.length x) y -- | /O(n)/ The 'isSuffixOf' function takes two ByteStrings and returns 'True' -- iff the first is a suffix of the second. -- -- The following holds: -- -- > isSuffixOf x y == reverse x `isPrefixOf` reverse y -- isSuffixOf :: ByteString -> ByteString -> Bool isSuffixOf x y = reverse x `isPrefixOf` reverse y --TODO: a better implementation -- --------------------------------------------------------------------- -- Zipping -- | /O(n)/ 'zip' takes two ByteStrings and returns a list of -- corresponding pairs of bytes. If one input ByteString is short, -- excess elements of the longer ByteString are discarded. This is -- equivalent to a pair of 'unpack' operations. zip :: ByteString -> ByteString -> [(Word8,Word8)] zip = zipWith (,) -- | 'zipWith' generalises 'zip' by zipping with the function given as -- the first argument, instead of a tupling function. For example, -- @'zipWith' (+)@ is applied to two ByteStrings to produce the list of -- corresponding sums. zipWith :: (Word8 -> Word8 -> a) -> ByteString -> ByteString -> [a] zipWith _ Empty _ = [] zipWith _ _ Empty = [] zipWith f (Chunk a as) (Chunk b bs) = go a as b bs where go x xs y ys = f (S.unsafeHead x) (S.unsafeHead y) : to (S.unsafeTail x) xs (S.unsafeTail y) ys to x Empty _ _ | S.null x = [] to _ _ y Empty | S.null y = [] to x xs y ys | not (S.null x) && not (S.null y) = go x xs y ys to x xs _ (Chunk y' ys) | not (S.null x) = go x xs y' ys to _ (Chunk x' xs) y ys | not (S.null y) = go x' xs y ys to _ (Chunk x' xs) _ (Chunk y' ys) = go x' xs y' ys -- | /O(n)/ 'unzip' transforms a list of pairs of bytes into a pair of -- ByteStrings. Note that this performs two 'pack' operations. unzip :: [(Word8,Word8)] -> (ByteString,ByteString) unzip ls = (pack (L.map fst ls), pack (L.map snd ls)) {-# INLINE unzip #-} -- --------------------------------------------------------------------- -- Special lists -- | /O(n)/ Return all initial segments of the given 'ByteString', shortest first. inits :: ByteString -> [ByteString] inits = (Empty :) . inits' where inits' Empty = [] inits' (Chunk c cs) = L.map (\c' -> Chunk c' Empty) (L.tail (S.inits c)) ++ L.map (Chunk c) (inits' cs) -- | /O(n)/ Return all final segments of the given 'ByteString', longest first. tails :: ByteString -> [ByteString] tails Empty = Empty : [] tails cs@(Chunk c cs') | S.length c == 1 = cs : tails cs' | otherwise = cs : tails (Chunk (S.unsafeTail c) cs') -- --------------------------------------------------------------------- -- Low level constructors -- | /O(n)/ Make a copy of the 'ByteString' with its own storage. -- This is mainly useful to allow the rest of the data pointed -- to by the 'ByteString' to be garbage collected, for example -- if a large string has been read in, and only a small part of it -- is needed in the rest of the program. copy :: ByteString -> ByteString copy cs = foldrChunks (Chunk . S.copy) Empty cs --TODO, we could coalese small blocks here --FIXME: probably not strict enough, if we're doing this to avoid retaining -- the parent blocks then we'd better copy strictly. -- --------------------------------------------------------------------- -- TODO defrag func that concatenates block together that are below a threshold -- defrag :: ByteString -> ByteString -- --------------------------------------------------------------------- -- Lazy ByteString IO -- -- Rule for when to close: is it expected to read the whole file? -- If so, close when done. -- -- | Read entire handle contents /lazily/ into a 'ByteString'. Chunks -- are read on demand, in at most @k@-sized chunks. It does not block -- waiting for a whole @k@-sized chunk, so if less than @k@ bytes are -- available then they will be returned immediately as a smaller chunk. -- -- The handle is closed on EOF. -- -- Note: the 'Handle' should be placed in binary mode with -- 'System.IO.hSetBinaryMode' for 'hGetContentsN' to -- work correctly. -- hGetContentsN :: Int -> Handle -> IO ByteString hGetContentsN k h = lazyRead -- TODO close on exceptions where lazyRead = unsafeInterleaveIO loop loop = do c <- S.hGetSome h k -- only blocks if there is no data available if S.null c then do hClose h >> return Empty else do cs <- lazyRead return (Chunk c cs) -- | Read @n@ bytes into a 'ByteString', directly from the -- specified 'Handle', in chunks of size @k@. -- hGetN :: Int -> Handle -> Int -> IO ByteString hGetN k h n | n > 0 = readChunks n where readChunks !i = do c <- S.hGet h (min k i) case S.length c of 0 -> return Empty m -> do cs <- readChunks (i - m) return (Chunk c cs) hGetN _ _ 0 = return Empty hGetN _ h n = illegalBufferSize h "hGet" n -- | hGetNonBlockingN is similar to 'hGetContentsN', except that it will never block -- waiting for data to become available, instead it returns only whatever data -- is available. Chunks are read on demand, in @k@-sized chunks. -- hGetNonBlockingN :: Int -> Handle -> Int -> IO ByteString hGetNonBlockingN k h n | n > 0= readChunks n where readChunks !i = do c <- S.hGetNonBlocking h (min k i) case S.length c of 0 -> return Empty m -> do cs <- readChunks (i - m) return (Chunk c cs) hGetNonBlockingN _ _ 0 = return Empty hGetNonBlockingN _ h n = illegalBufferSize h "hGetNonBlocking" n illegalBufferSize :: Handle -> String -> Int -> IO a illegalBufferSize handle fn sz = ioError (mkIOError illegalOperationErrorType msg (Just handle) Nothing) --TODO: System.IO uses InvalidArgument here, but it's not exported :-( where msg = fn ++ ": illegal ByteString size " ++ showsPrec 9 sz [] -- | Read entire handle contents /lazily/ into a 'ByteString'. Chunks -- are read on demand, using the default chunk size. -- -- Once EOF is encountered, the Handle is closed. -- -- Note: the 'Handle' should be placed in binary mode with -- 'System.IO.hSetBinaryMode' for 'hGetContents' to -- work correctly. -- hGetContents :: Handle -> IO ByteString hGetContents = hGetContentsN defaultChunkSize -- | Read @n@ bytes into a 'ByteString', directly from the specified 'Handle'. -- hGet :: Handle -> Int -> IO ByteString hGet = hGetN defaultChunkSize -- | hGetNonBlocking is similar to 'hGet', except that it will never block -- waiting for data to become available, instead it returns only whatever data -- is available. If there is no data available to be read, 'hGetNonBlocking' -- returns 'empty'. -- -- Note: on Windows and with Haskell implementation other than GHC, this -- function does not work correctly; it behaves identically to 'hGet'. -- hGetNonBlocking :: Handle -> Int -> IO ByteString hGetNonBlocking = hGetNonBlockingN defaultChunkSize -- | Read an entire file /lazily/ into a 'ByteString'. -- The Handle will be held open until EOF is encountered. -- readFile :: FilePath -> IO ByteString readFile f = openBinaryFile f ReadMode >>= hGetContents -- | Write a 'ByteString' to a file. -- writeFile :: FilePath -> ByteString -> IO () writeFile f txt = bracket (openBinaryFile f WriteMode) hClose (\hdl -> hPut hdl txt) -- | Append a 'ByteString' to a file. -- appendFile :: FilePath -> ByteString -> IO () appendFile f txt = bracket (openBinaryFile f AppendMode) hClose (\hdl -> hPut hdl txt) -- | getContents. Equivalent to hGetContents stdin. Will read /lazily/ -- getContents :: IO ByteString getContents = hGetContents stdin -- | Outputs a 'ByteString' to the specified 'Handle'. -- hPut :: Handle -> ByteString -> IO () hPut h cs = foldrChunks (\c rest -> S.hPut h c >> rest) (return ()) cs -- | Similar to 'hPut' except that it will never block. Instead it returns -- any tail that did not get written. This tail may be 'empty' in the case that -- the whole string was written, or the whole original string if nothing was -- written. Partial writes are also possible. -- -- Note: on Windows and with Haskell implementation other than GHC, this -- function does not work correctly; it behaves identically to 'hPut'. -- hPutNonBlocking :: Handle -> ByteString -> IO ByteString hPutNonBlocking _ Empty = return Empty hPutNonBlocking h bs@(Chunk c cs) = do c' <- S.hPutNonBlocking h c case S.length c' of l' | l' == S.length c -> hPutNonBlocking h cs 0 -> return bs _ -> return (Chunk c' cs) -- | A synonym for @hPut@, for compatibility -- hPutStr :: Handle -> ByteString -> IO () hPutStr = hPut -- | Write a ByteString to stdout putStr :: ByteString -> IO () putStr = hPut stdout -- | Write a ByteString to stdout, appending a newline byte -- putStrLn :: ByteString -> IO () putStrLn ps = hPut stdout ps >> hPut stdout (singleton 0x0a) {-# DEPRECATED putStrLn "Use Data.ByteString.Lazy.Char8.putStrLn instead. (Functions that rely on ASCII encodings belong in Data.ByteString.Lazy.Char8)" #-} -- | The interact function takes a function of type @ByteString -> ByteString@ -- as its argument. The entire input from the standard input device is passed -- to this function as its argument, and the resulting string is output on the -- standard output device. -- interact :: (ByteString -> ByteString) -> IO () interact transformer = putStr . transformer =<< getContents -- --------------------------------------------------------------------- -- Internal utilities -- Common up near identical calls to `error' to reduce the number -- constant strings created when compiled: errorEmptyList :: String -> a errorEmptyList fun = moduleError fun "empty ByteString" moduleError :: String -> String -> a moduleError fun msg = error ("Data.Vector.Storable.ByteString.Lazy." ++ fun ++ ':':' ':msg) -- reverse a list of non-empty chunks into a lazy ByteString revNonEmptyChunks :: [P.ByteString] -> ByteString revNonEmptyChunks cs = L.foldl' (flip Chunk) Empty cs -- reverse a list of possibly-empty chunks into a lazy ByteString revChunks :: [P.ByteString] -> ByteString revChunks cs = L.foldl' (flip chunk) Empty cs -- | 'findIndexOrEnd' is a variant of findIndex, that returns the length -- of the string if no element is found, rather than Nothing. findIndexOrEnd :: (Word8 -> Bool) -> P.ByteString -> Int findIndexOrEnd k v = S.inlinePerformIO $ withForeignPtr fp $ \f -> go f 0 where (fp, l) = VS.unsafeToForeignPtr0 v go !ptr !n | n >= l = return l | otherwise = do w <- peek ptr if k w then return n else go (ptr `plusPtr` 1) (n+1) {-# INLINE findIndexOrEnd #-}