{-# OPTIONS_GHC -cpp -fno-warn-orphans #-}
-- |
-- Module : Data.ByteString.Lazy.Char8
-- Copyright : (c) Don Stewart 2006
-- License : BSD-style
--
-- Maintainer : [email protected]
-- Stability : experimental
-- Portability : non-portable (imports Data.ByteString.Lazy)
--
-- Manipulate /lazy/ 'ByteString's using 'Char' operations. All Chars will
-- be truncated to 8 bits. It can be expected that these functions will
-- run at identical speeds to their 'Data.Word.Word8' equivalents in
-- "Data.ByteString.Lazy".
--
-- This module is intended to be imported @qualified@, to avoid name
-- clashes with "Prelude" functions. eg.
--
-- > import qualified Data.ByteString.Lazy.Char8 as C
--
module Data.ByteString.Lazy.Char8 (
-- * The @ByteString@ type
ByteString, -- instances: Eq, Ord, Show, Read, Data, Typeable
-- * Introducing and eliminating 'ByteString's
empty, -- :: ByteString
singleton, -- :: Char -> ByteString
pack, -- :: String -> ByteString
unpack, -- :: ByteString -> String
fromChunks, -- :: [Strict.ByteString] -> ByteString
toChunks, -- :: ByteString -> [Strict.ByteString]
-- * Basic interface
cons, -- :: Char -> ByteString -> ByteString
cons', -- :: Char -> ByteString -> ByteString
snoc, -- :: ByteString -> Char -> ByteString
append, -- :: ByteString -> ByteString -> ByteString
head, -- :: ByteString -> Char
uncons, -- :: ByteString -> Maybe (Char, ByteString)
last, -- :: ByteString -> Char
tail, -- :: ByteString -> ByteString
init, -- :: ByteString -> ByteString
null, -- :: ByteString -> Bool
length, -- :: ByteString -> Int64
-- * Transformating ByteStrings
map, -- :: (Char -> Char) -> ByteString -> ByteString
reverse, -- :: ByteString -> ByteString
-- intersperse, -- :: Char -> ByteString -> ByteString
transpose, -- :: [ByteString] -> [ByteString]
-- * Reducing 'ByteString's (folds)
foldl, -- :: (a -> Char -> a) -> a -> ByteString -> a
foldl', -- :: (a -> Char -> a) -> a -> ByteString -> a
foldl1, -- :: (Char -> Char -> Char) -> ByteString -> Char
foldl1', -- :: (Char -> Char -> Char) -> ByteString -> Char
foldr, -- :: (Char -> a -> a) -> a -> ByteString -> a
foldr1, -- :: (Char -> Char -> Char) -> ByteString -> Char
-- ** Special folds
concat, -- :: [ByteString] -> ByteString
concatMap, -- :: (Char -> ByteString) -> ByteString -> ByteString
any, -- :: (Char -> Bool) -> ByteString -> Bool
all, -- :: (Char -> Bool) -> ByteString -> Bool
maximum, -- :: ByteString -> Char
minimum, -- :: ByteString -> Char
-- * Building ByteStrings
-- ** Scans
scanl, -- :: (Char -> Char -> Char) -> Char -> ByteString -> ByteString
-- scanl1, -- :: (Char -> Char -> Char) -> ByteString -> ByteString
-- scanr, -- :: (Char -> Char -> Char) -> Char -> ByteString -> ByteString
-- scanr1, -- :: (Char -> Char -> Char) -> ByteString -> ByteString
-- ** Accumulating maps
mapAccumL, -- :: (acc -> Char -> (acc, Char)) -> acc -> ByteString -> (acc, ByteString)
mapIndexed, -- :: (Int64 -> Char -> Char) -> ByteString -> ByteString
-- ** Infinite ByteStrings
repeat, -- :: Char -> ByteString
replicate, -- :: Int64 -> Char -> ByteString
cycle, -- :: ByteString -> ByteString
iterate, -- :: (Char -> Char) -> Char -> ByteString
-- ** Unfolding
unfoldr, -- :: (a -> Maybe (Char, a)) -> a -> ByteString
-- * Substrings
-- ** Breaking strings
take, -- :: Int64 -> ByteString -> ByteString
drop, -- :: Int64 -> ByteString -> ByteString
splitAt, -- :: Int64 -> ByteString -> (ByteString, ByteString)
takeWhile, -- :: (Char -> Bool) -> ByteString -> ByteString
dropWhile, -- :: (Char -> Bool) -> ByteString -> ByteString
span, -- :: (Char -> Bool) -> ByteString -> (ByteString, ByteString)
break, -- :: (Char -> Bool) -> ByteString -> (ByteString, ByteString)
group, -- :: ByteString -> [ByteString]
groupBy, -- :: (Char -> Char -> Bool) -> ByteString -> [ByteString]
inits, -- :: ByteString -> [ByteString]
tails, -- :: ByteString -> [ByteString]
-- ** Breaking into many substrings
split, -- :: Char -> ByteString -> [ByteString]
splitWith, -- :: (Char -> Bool) -> ByteString -> [ByteString]
-- ** Breaking into lines and words
lines, -- :: ByteString -> [ByteString]
words, -- :: ByteString -> [ByteString]
unlines, -- :: [ByteString] -> ByteString
unwords, -- :: ByteString -> [ByteString]
-- ** Joining strings
join, -- :: ByteString -> [ByteString] -> ByteString
-- * Predicates
isPrefixOf, -- :: ByteString -> ByteString -> Bool
-- isSuffixOf, -- :: ByteString -> ByteString -> Bool
-- * Searching ByteStrings
-- ** Searching by equality
elem, -- :: Char -> ByteString -> Bool
notElem, -- :: Char -> ByteString -> Bool
-- ** Searching with a predicate
find, -- :: (Char -> Bool) -> ByteString -> Maybe Char
filter, -- :: (Char -> Bool) -> ByteString -> ByteString
-- partition -- :: (Char -> Bool) -> ByteString -> (ByteString, ByteString)
-- * Indexing ByteStrings
index, -- :: ByteString -> Int64 -> Char
elemIndex, -- :: Char -> ByteString -> Maybe Int64
elemIndices, -- :: Char -> ByteString -> [Int64]
findIndex, -- :: (Char -> Bool) -> ByteString -> Maybe Int64
findIndices, -- :: (Char -> Bool) -> ByteString -> [Int64]
count, -- :: Char -> ByteString -> Int64
-- * Zipping and unzipping ByteStrings
zip, -- :: ByteString -> ByteString -> [(Char,Char)]
zipWith, -- :: (Char -> Char -> c) -> ByteString -> ByteString -> [c]
-- unzip, -- :: [(Char,Char)] -> (ByteString,ByteString)
-- * Ordered ByteStrings
-- sort, -- :: ByteString -> ByteString
copy, -- :: ByteString -> ByteString
-- * Reading from ByteStrings
readInt,
readInteger,
-- * 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 -> Int64 -> IO ByteString
hPut, -- :: Handle -> ByteString -> IO ()
hGetNonBlocking, -- :: Handle -> IO ByteString
-- hGetN, -- :: Int -> Handle -> Int64 -> IO ByteString
-- hGetContentsN, -- :: Int -> Handle -> IO ByteString
-- hGetNonBlockingN, -- :: Int -> Handle -> IO ByteString
) where
-- Functions transparently exported
import Data.ByteString.Lazy
(ByteString, fromChunks, toChunks
,empty,null,length,tail,init,append,reverse,transpose,cycle
,concat,take,drop,splitAt,join,isPrefixOf,group,inits,tails,copy
,hGetContents, hGet, hPut, getContents
,hGetNonBlocking
,putStr, putStrLn, interact)
-- Functions we need to wrap.
import qualified Data.ByteString.Lazy as L
import qualified Data.ByteString as B
import qualified Data.ByteString.Base as Base
import Data.ByteString.Base (LazyByteString(LPS))
import Data.ByteString.Base (w2c, c2w, isSpaceWord8)
import Data.Int (Int64)
import qualified Data.List as List (intersperse)
import qualified Prelude as P
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
,unwords,words,maximum,minimum,all,concatMap,scanl,scanl1,foldl1,foldr1
,readFile,writeFile,appendFile,replicate,getContents,getLine,putStr,putStrLn
,zip,zipWith,unzip,notElem,repeat,iterate,interact,cycle)
import System.IO (hClose,openFile,IOMode(..))
#ifndef __NHC__
import Control.Exception (bracket)
#else
import IO (bracket)
#endif
#define STRICT1(f) f a | a `seq` False = undefined
#define STRICT2(f) f a b | a `seq` b `seq` False = undefined
#define STRICT3(f) f a b c | a `seq` b `seq` c `seq` False = undefined
#define STRICT4(f) f a b c d | a `seq` b `seq` c `seq` d `seq` False = undefined
#define STRICT5(f) f a b c d e | a `seq` b `seq` c `seq` d `seq` e `seq` False = undefined
------------------------------------------------------------------------
-- | /O(1)/ Convert a 'Char' into a 'ByteString'
singleton :: Char -> ByteString
singleton = L.singleton . c2w
{-# INLINE singleton #-}
-- | /O(n)/ Convert a 'String' into a 'ByteString'.
pack :: [Char] -> ByteString
pack = L.pack. P.map c2w
-- | /O(n)/ Converts a 'ByteString' to a 'String'.
unpack :: ByteString -> [Char]
unpack = P.map w2c . L.unpack
{-# INLINE unpack #-}
-- | /O(1)/ 'cons' is analogous to '(:)' for lists.
cons :: Char -> ByteString -> ByteString
cons = L.cons . c2w
{-# 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' :: Char -> ByteString -> ByteString
cons' = L.cons' . c2w
{-# INLINE cons' #-}
-- | /O(n)/ Append a Char to the end of a 'ByteString'. Similar to
-- 'cons', this function performs a memcpy.
snoc :: ByteString -> Char -> ByteString
snoc p = L.snoc p . c2w
{-# INLINE snoc #-}
-- | /O(1)/ Extract the first element of a ByteString, which must be non-empty.
head :: ByteString -> Char
head = w2c . L.head
{-# INLINE head #-}
-- | /O(1)/ Extract the head and tail of a ByteString, returning Nothing
-- if it is empty.
uncons :: ByteString -> Maybe (Char, ByteString)
uncons bs = case L.uncons bs of
Nothing -> Nothing
Just (w, bs') -> Just (w2c w, bs')
{-# INLINE uncons #-}
-- | /O(1)/ Extract the last element of a packed string, which must be non-empty.
last :: ByteString -> Char
last = w2c . L.last
{-# INLINE last #-}
-- | /O(n)/ 'map' @f xs@ is the ByteString obtained by applying @f@ to each element of @xs@
map :: (Char -> Char) -> ByteString -> ByteString
map f = L.map (c2w . f . w2c)
{-# INLINE map #-}
-- | '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 -> Char -> a) -> a -> ByteString -> a
foldl f = L.foldl (\a c -> f a (w2c c))
{-# INLINE foldl #-}
-- | 'foldl\'' is like foldl, but strict in the accumulator.
foldl' :: (a -> Char -> a) -> a -> ByteString -> a
foldl' f = L.foldl' (\a c -> f a (w2c c))
{-# INLINE foldl' #-}
-- | 'foldr', applied to a binary operator, a starting value
-- (typically the right-identity of the operator), and a packed string,
-- reduces the packed string using the binary operator, from right to left.
foldr :: (Char -> a -> a) -> a -> ByteString -> a
foldr f = L.foldr (\c a -> f (w2c c) a)
{-# INLINE foldr #-}
-- | 'foldl1' is a variant of 'foldl' that has no starting value
-- argument, and thus must be applied to non-empty 'ByteStrings'.
foldl1 :: (Char -> Char -> Char) -> ByteString -> Char
foldl1 f ps = w2c (L.foldl1 (\x y -> c2w (f (w2c x) (w2c y))) ps)
{-# INLINE foldl1 #-}
-- | 'foldl1\'' is like 'foldl1', but strict in the accumulator.
foldl1' :: (Char -> Char -> Char) -> ByteString -> Char
foldl1' f ps = w2c (L.foldl1' (\x y -> c2w (f (w2c x) (w2c y))) ps)
-- | 'foldr1' is a variant of 'foldr' that has no starting value argument,
-- and thus must be applied to non-empty 'ByteString's
foldr1 :: (Char -> Char -> Char) -> ByteString -> Char
foldr1 f ps = w2c (L.foldr1 (\x y -> c2w (f (w2c x) (w2c y))) ps)
{-# INLINE foldr1 #-}
-- | Map a function over a 'ByteString' and concatenate the results
concatMap :: (Char -> ByteString) -> ByteString -> ByteString
concatMap f = L.concatMap (f . w2c)
{-# INLINE concatMap #-}
-- | Applied to a predicate and a ByteString, 'any' determines if
-- any element of the 'ByteString' satisfies the predicate.
any :: (Char -> Bool) -> ByteString -> Bool
any f = L.any (f . w2c)
{-# INLINE any #-}
-- | Applied to a predicate and a 'ByteString', 'all' determines if
-- all elements of the 'ByteString' satisfy the predicate.
all :: (Char -> Bool) -> ByteString -> Bool
all f = L.all (f . w2c)
{-# INLINE all #-}
-- | 'maximum' returns the maximum value from a 'ByteString'
maximum :: ByteString -> Char
maximum = w2c . L.maximum
{-# INLINE maximum #-}
-- | 'minimum' returns the minimum value from a 'ByteString'
minimum :: ByteString -> Char
minimum = w2c . L.minimum
{-# INLINE minimum #-}
-- ---------------------------------------------------------------------
-- 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 :: (Char -> Char -> Char) -> Char -> ByteString -> ByteString
scanl f z = L.scanl (\a b -> c2w (f (w2c a) (w2c b))) (c2w z)
-- | 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 -> Char -> (acc, Char)) -> acc -> ByteString -> (acc, ByteString)
mapAccumL f = L.mapAccumL (\a w -> case f a (w2c w) of (a',c) -> (a', c2w c))
-- | /O(n)/ map Char functions, provided with the index at each position
mapIndexed :: (Int -> Char -> Char) -> ByteString -> ByteString
mapIndexed f = L.mapIndexed (\i w -> c2w (f i (w2c w)))
------------------------------------------------------------------------
-- Generating and unfolding ByteStrings
-- | @'iterate' f x@ returns an infinite ByteString of repeated applications
-- of @f@ to @x@:
--
-- > iterate f x == [x, f x, f (f x), ...]
--
iterate :: (Char -> Char) -> Char -> ByteString
iterate f = L.iterate (c2w . f . w2c) . c2w
-- | @'repeat' x@ is an infinite ByteString, with @x@ the value of every
-- element.
--
repeat :: Char -> ByteString
repeat = L.repeat . c2w
-- | /O(n)/ @'replicate' n x@ is a ByteString of length @n@ with @x@
-- the value of every element.
--
replicate :: Int64 -> Char -> ByteString
replicate w c = L.replicate w (c2w c)
-- | /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 (Char, a)) -> a -> ByteString
unfoldr f = L.unfoldr $ \a -> case f a of
Nothing -> Nothing
Just (c, a') -> Just (c2w c, a')
------------------------------------------------------------------------
-- | 'takeWhile', applied to a predicate @p@ and a ByteString @xs@,
-- returns the longest prefix (possibly empty) of @xs@ of elements that
-- satisfy @p@.
takeWhile :: (Char -> Bool) -> ByteString -> ByteString
takeWhile f = L.takeWhile (f . w2c)
{-# INLINE takeWhile #-}
-- | 'dropWhile' @p xs@ returns the suffix remaining after 'takeWhile' @p xs@.
dropWhile :: (Char -> Bool) -> ByteString -> ByteString
dropWhile f = L.dropWhile (f . w2c)
{-# INLINE dropWhile #-}
-- | 'break' @p@ is equivalent to @'span' ('not' . p)@.
break :: (Char -> Bool) -> ByteString -> (ByteString, ByteString)
break f = L.break (f . w2c)
{-# INLINE break #-}
-- | 'span' @p xs@ breaks the ByteString into two segments. It is
-- equivalent to @('takeWhile' p xs, 'dropWhile' p xs)@
span :: (Char -> Bool) -> ByteString -> (ByteString, ByteString)
span f = L.span (f . w2c)
{-# INLINE span #-}
{-
-- | 'breakChar' breaks its ByteString argument at the first occurence
-- of the specified Char. It is more efficient than 'break' as it is
-- implemented with @memchr(3)@. I.e.
--
-- > break (=='c') "abcd" == breakChar 'c' "abcd"
--
breakChar :: Char -> ByteString -> (ByteString, ByteString)
breakChar = L.breakByte . c2w
{-# INLINE breakChar #-}
-- | 'spanChar' breaks its ByteString argument at the first
-- occurence of a Char other than its argument. It is more efficient
-- than 'span (==)'
--
-- > span (=='c') "abcd" == spanByte 'c' "abcd"
--
spanChar :: Char -> ByteString -> (ByteString, ByteString)
spanChar = L.spanByte . c2w
{-# INLINE spanChar #-}
-}
--
-- TODO, more rules for breakChar*
--
-- | /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
--
-- > join [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 :: Char -> ByteString -> [ByteString]
split = L.split . c2w
{-# INLINE split #-}
-- | /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 :: (Char -> Bool) -> ByteString -> [ByteString]
splitWith f = L.splitWith (f . w2c)
{-# INLINE splitWith #-}
-- | The 'groupBy' function is the non-overloaded version of 'group'.
groupBy :: (Char -> Char -> Bool) -> ByteString -> [ByteString]
groupBy k = L.groupBy (\a b -> k (w2c a) (w2c b))
-- | /O(1)/ 'ByteString' index (subscript) operator, starting from 0.
index :: ByteString -> Int64 -> Char
index = (w2c .) . L.index
{-# INLINE index #-}
-- | /O(n)/ The 'elemIndex' function returns the index of the first
-- element in the given 'ByteString' which is equal (by memchr) to the
-- query element, or 'Nothing' if there is no such element.
elemIndex :: Char -> ByteString -> Maybe Int64
elemIndex = L.elemIndex . c2w
{-# INLINE elemIndex #-}
-- | /O(n)/ The 'elemIndices' function extends 'elemIndex', by returning
-- the indices of all elements equal to the query element, in ascending order.
elemIndices :: Char -> ByteString -> [Int64]
elemIndices = L.elemIndices . c2w
{-# INLINE elemIndices #-}
-- | The 'findIndex' function takes a predicate and a 'ByteString' and
-- returns the index of the first element in the ByteString satisfying the predicate.
findIndex :: (Char -> Bool) -> ByteString -> Maybe Int64
findIndex f = L.findIndex (f . w2c)
{-# INLINE findIndex #-}
-- | The 'findIndices' function extends 'findIndex', by returning the
-- indices of all elements satisfying the predicate, in ascending order.
findIndices :: (Char -> Bool) -> ByteString -> [Int64]
findIndices f = L.findIndices (f . w2c)
-- | count returns the number of times its argument appears in the ByteString
--
-- > count == length . elemIndices
-- > count '\n' == length . lines
--
-- But more efficiently than using length on the intermediate list.
count :: Char -> ByteString -> Int64
count c = L.count (c2w c)
-- | /O(n)/ 'elem' is the 'ByteString' membership predicate. This
-- implementation uses @memchr(3)@.
elem :: Char -> ByteString -> Bool
elem c = L.elem (c2w c)
{-# INLINE elem #-}
-- | /O(n)/ 'notElem' is the inverse of 'elem'
notElem :: Char -> ByteString -> Bool
notElem c = L.notElem (c2w c)
{-# INLINE notElem #-}
-- | /O(n)/ 'filter', applied to a predicate and a ByteString,
-- returns a ByteString containing those characters that satisfy the
-- predicate.
filter :: (Char -> Bool) -> ByteString -> ByteString
filter f = L.filter (f . w2c)
{-# INLINE filter #-}
-- | /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 :: (Char -> Bool) -> ByteString -> Maybe Char
find f ps = w2c `fmap` L.find (f . w2c) ps
{-# INLINE find #-}
{-
-- | /O(n)/ A first order equivalent of /filter . (==)/, for the common
-- case of filtering a single Char. It is more efficient to use
-- filterChar in this case.
--
-- > filterChar == filter . (==)
--
-- filterChar is around 10x faster, and uses much less space, than its
-- filter equivalent
--
filterChar :: Char -> ByteString -> ByteString
filterChar c = L.filterByte (c2w c)
{-# INLINE filterChar #-}
-- | /O(n)/ A first order equivalent of /filter . (\/=)/, for the common
-- case of filtering a single Char out of a list. It is more efficient
-- to use /filterNotChar/ in this case.
--
-- > filterNotChar == filter . (/=)
--
-- filterNotChar is around 3x faster, and uses much less space, than its
-- filter equivalent
--
filterNotChar :: Char -> ByteString -> ByteString
filterNotChar c = L.filterNotByte (c2w c)
{-# INLINE filterNotChar #-}
-}
-- | /O(n)/ 'zip' takes two ByteStrings and returns a list of
-- corresponding pairs of Chars. If one input ByteString is short,
-- excess elements of the longer ByteString are discarded. This is
-- equivalent to a pair of 'unpack' operations, and so space
-- usage may be large for multi-megabyte ByteStrings
zip :: ByteString -> ByteString -> [(Char,Char)]
zip ps qs
| L.null ps || L.null qs = []
| otherwise = (head ps, head qs) : zip (L.tail ps) (L.tail qs)
-- | '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 :: (Char -> Char -> a) -> ByteString -> ByteString -> [a]
zipWith f = L.zipWith ((. w2c) . f . w2c)
-- | 'lines' breaks a ByteString up into a list of ByteStrings at
-- newline Chars. The resulting strings do not contain newlines.
--
lines :: ByteString -> [ByteString]
lines (LPS []) = []
lines (LPS (x:xs)) = loop0 x xs
where
-- this is a really performance sensitive function but the
-- chunked representation makes the general case a bit expensive
-- however assuming a large chunk size and normalish line lengths
-- we will find line endings much more frequently than chunk
-- endings so it makes sense to optimise for that common case.
-- So we partition into two special cases depending on whether we
-- are keeping back a list of chunks that will eventually be output
-- once we get to the end of the current line.
-- the common special case where we have no existing chunks of
-- the current line
loop0 :: B.ByteString -> [B.ByteString] -> [ByteString]
STRICT2(loop0)
loop0 ps pss =
case B.elemIndex (c2w '\n') ps of
Nothing -> case pss of
[] | B.null ps -> []
| otherwise -> LPS [ps] : []
(ps':pss')
| B.null ps -> loop0 ps' pss'
| otherwise -> loop ps' [ps] pss'
Just n | n /= 0 -> LPS [Base.unsafeTake n ps]
: loop0 (Base.unsafeDrop (n+1) ps) pss
| otherwise -> loop0 (Base.unsafeTail ps) pss
-- the general case when we are building a list of chunks that are
-- part of the same line
loop :: B.ByteString -> [B.ByteString] -> [B.ByteString] -> [ByteString]
STRICT3(loop)
loop ps line pss =
case B.elemIndex (c2w '\n') ps of
Nothing ->
case pss of
[] -> let ps' | B.null ps = P.reverse line
| otherwise = P.reverse (ps : line)
in ps' `seq` (LPS ps' : [])
(ps':pss')
| B.null ps -> loop ps' line pss'
| otherwise -> loop ps' (ps : line) pss'
Just n ->
let ps' | n == 0 = P.reverse line
| otherwise = P.reverse (Base.unsafeTake n ps : line)
in ps' `seq` (LPS ps' : loop0 (Base.unsafeDrop (n+1) ps) pss)
-- | 'unlines' is an inverse operation to 'lines'. It joins lines,
-- after appending a terminating newline to each.
unlines :: [ByteString] -> ByteString
unlines [] = empty
unlines ss = (concat $ List.intersperse nl ss) `append` nl -- half as much space
where nl = singleton '\n'
-- | 'words' breaks a ByteString up into a list of words, which
-- were delimited by Chars representing white space. And
--
-- > tokens isSpace = words
--
words :: ByteString -> [ByteString]
words = P.filter (not . L.null) . L.splitWith isSpaceWord8
{-# INLINE words #-}
-- | The 'unwords' function is analogous to the 'unlines' function, on words.
unwords :: [ByteString] -> ByteString
unwords = join (singleton ' ')
{-# INLINE unwords #-}
-- | readInt reads an Int from the beginning of the ByteString. If
-- there is no integer at the beginning of the string, it returns
-- Nothing, otherwise it just returns the int read, and the rest of the
-- string.
readInt :: ByteString -> Maybe (Int, ByteString)
readInt (LPS []) = Nothing
readInt (LPS (x:xs)) =
case w2c (Base.unsafeHead x) of
'-' -> loop True 0 0 (Base.unsafeTail x) xs
'+' -> loop False 0 0 (Base.unsafeTail x) xs
_ -> loop False 0 0 x xs
where loop :: Bool -> Int -> Int -> B.ByteString -> [B.ByteString] -> Maybe (Int, ByteString)
STRICT5(loop)
loop neg i n ps pss
| B.null ps = case pss of
[] -> end neg i n ps pss
(ps':pss') -> loop neg i n ps' pss'
| otherwise =
case Base.unsafeHead ps of
w | w >= 0x30
&& w <= 0x39 -> loop neg (i+1)
(n * 10 + (fromIntegral w - 0x30))
(Base.unsafeTail ps) pss
| otherwise -> end neg i n ps pss
end _ 0 _ _ _ = Nothing
end neg _ n ps pss = let n' | neg = negate n
| otherwise = n
ps' | B.null ps = pss
| otherwise = ps:pss
in n' `seq` ps' `seq` Just $! (n', LPS ps')
-- | readInteger reads an Integer from the beginning of the ByteString. If
-- there is no integer at the beginning of the string, it returns Nothing,
-- otherwise it just returns the int read, and the rest of the string.
readInteger :: ByteString -> Maybe (Integer, ByteString)
readInteger (LPS []) = Nothing
readInteger (LPS (x:xs)) =
case w2c (Base.unsafeHead x) of
'-' -> first (Base.unsafeTail x) xs >>= \(n, bs) -> return (-n, bs)
'+' -> first (Base.unsafeTail x) xs
_ -> first x xs
where first ps pss
| B.null ps = case pss of
[] -> Nothing
(ps':pss') -> first' ps' pss'
| otherwise = first' ps pss
first' ps pss = case Base.unsafeHead ps of
w | w >= 0x30 && w <= 0x39 -> Just $
loop 1 (fromIntegral w - 0x30) [] (Base.unsafeTail ps) pss
| otherwise -> Nothing
loop :: Int -> Int -> [Integer]
-> B.ByteString -> [B.ByteString] -> (Integer, ByteString)
STRICT5(loop)
loop d acc ns ps pss
| B.null ps = case pss of
[] -> combine d acc ns ps pss
(ps':pss') -> loop d acc ns ps' pss'
| otherwise =
case Base.unsafeHead ps of
w | w >= 0x30 && w <= 0x39 ->
if d < 9 then loop (d+1)
(10*acc + (fromIntegral w - 0x30))
ns (Base.unsafeTail ps) pss
else loop 1 (fromIntegral w - 0x30)
(fromIntegral acc : ns)
(Base.unsafeTail ps) pss
| otherwise -> combine d acc ns ps pss
combine _ acc [] ps pss = end (fromIntegral acc) ps pss
combine d acc ns ps pss =
end (10^d * combine1 1000000000 ns + fromIntegral acc) ps pss
combine1 _ [n] = n
combine1 b ns = combine1 (b*b) $ combine2 b ns
combine2 b (n:m:ns) = let t = n+m*b in t `seq` (t : combine2 b ns)
combine2 _ ns = ns
end n ps pss = let ps' | B.null ps = pss
| otherwise = ps:pss
in ps' `seq` (n, LPS ps')
-- | Read an entire file /lazily/ into a 'ByteString'. Use 'text mode'
-- on Windows to interpret newlines
readFile :: FilePath -> IO ByteString
readFile f = openFile f ReadMode >>= hGetContents
-- | Write a 'ByteString' to a file.
writeFile :: FilePath -> ByteString -> IO ()
writeFile f txt = bracket (openFile f WriteMode) hClose
(\hdl -> hPut hdl txt)
-- | Append a 'ByteString' to a file.
appendFile :: FilePath -> ByteString -> IO ()
appendFile f txt = bracket (openFile f AppendMode) hClose
(\hdl -> hPut hdl txt)
|
