| Copyright | (c) Don Stewart 2006-2008 (c) Duncan Coutts 2006-2011 |
|---|---|
| License | BSD-style |
| Maintainer | dons00@gmail.com, duncan@community.haskell.org |
| Stability | stable |
| Portability | portable |
| Safe Haskell | Trustworthy |
| Language | Haskell2010 |
Data.ByteString.Lazy.Char8
Contents
- The
ByteStringtype - Introducing and eliminating
ByteStrings - Basic interface
- Transforming ByteStrings
- Reducing
ByteStrings (folds) - Building ByteStrings
- Substrings
- Predicates
- Searching ByteStrings
- Indexing ByteStrings
- Zipping and unzipping ByteStrings
- Ordered ByteStrings
- Low level conversions
- Reading from ByteStrings
- I/O with
ByteStrings
Description
Manipulate lazy ByteStrings 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 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
The Char8 interface to bytestrings provides an instance of IsString
for the ByteString type, enabling you to use string literals, and
have them implicitly packed to ByteStrings.
Use {-# LANGUAGE OverloadedStrings #-} to enable this.
Synopsis
- data ByteString
- empty :: ByteString
- singleton :: Char -> ByteString
- pack :: [Char] -> ByteString
- unpack :: ByteString -> [Char]
- fromChunks :: [ByteString] -> ByteString
- toChunks :: ByteString -> [ByteString]
- fromStrict :: ByteString -> ByteString
- toStrict :: ByteString -> ByteString
- 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 :: HasCallStack => ByteString -> ByteString
- unsnoc :: ByteString -> Maybe (ByteString, Char)
- init :: HasCallStack => ByteString -> ByteString
- null :: ByteString -> Bool
- length :: ByteString -> Int64
- map :: (Char -> Char) -> ByteString -> ByteString
- reverse :: ByteString -> ByteString
- intersperse :: Char -> ByteString -> ByteString
- intercalate :: ByteString -> [ByteString] -> ByteString
- transpose :: [ByteString] -> [ByteString]
- 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
- foldr' :: (Char -> a -> a) -> a -> ByteString -> a
- foldr1 :: (Char -> Char -> Char) -> ByteString -> Char
- foldr1' :: (Char -> Char -> Char) -> ByteString -> Char
- concat :: [ByteString] -> ByteString
- concatMap :: (Char -> ByteString) -> ByteString -> ByteString
- any :: (Char -> Bool) -> ByteString -> Bool
- all :: (Char -> Bool) -> ByteString -> Bool
- maximum :: ByteString -> Char
- minimum :: ByteString -> Char
- compareLength :: ByteString -> Int64 -> Ordering
- 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
- mapAccumL :: (acc -> Char -> (acc, Char)) -> acc -> ByteString -> (acc, ByteString)
- mapAccumR :: (acc -> Char -> (acc, Char)) -> acc -> ByteString -> (acc, ByteString)
- repeat :: Char -> ByteString
- replicate :: Int64 -> Char -> ByteString
- cycle :: HasCallStack => ByteString -> ByteString
- iterate :: (Char -> Char) -> Char -> ByteString
- unfoldr :: (a -> Maybe (Char, a)) -> a -> ByteString
- take :: Int64 -> ByteString -> ByteString
- takeEnd :: Int64 -> ByteString -> ByteString
- drop :: Int64 -> ByteString -> ByteString
- dropEnd :: Int64 -> ByteString -> ByteString
- splitAt :: Int64 -> ByteString -> (ByteString, ByteString)
- takeWhile :: (Char -> Bool) -> ByteString -> ByteString
- takeWhileEnd :: (Char -> Bool) -> ByteString -> ByteString
- dropWhile :: (Char -> Bool) -> ByteString -> ByteString
- dropWhileEnd :: (Char -> Bool) -> ByteString -> ByteString
- span :: (Char -> Bool) -> ByteString -> (ByteString, ByteString)
- spanEnd :: (Char -> Bool) -> ByteString -> (ByteString, ByteString)
- break :: (Char -> Bool) -> ByteString -> (ByteString, ByteString)
- breakEnd :: (Char -> Bool) -> ByteString -> (ByteString, ByteString)
- group :: ByteString -> [ByteString]
- groupBy :: (Char -> Char -> Bool) -> ByteString -> [ByteString]
- inits :: ByteString -> [ByteString]
- tails :: ByteString -> [ByteString]
- initsNE :: ByteString -> NonEmpty ByteString
- tailsNE :: ByteString -> NonEmpty ByteString
- stripPrefix :: ByteString -> ByteString -> Maybe ByteString
- stripSuffix :: ByteString -> ByteString -> Maybe ByteString
- split :: Char -> ByteString -> [ByteString]
- splitWith :: (Char -> Bool) -> ByteString -> [ByteString]
- lines :: ByteString -> [ByteString]
- words :: ByteString -> [ByteString]
- unlines :: [ByteString] -> ByteString
- unwords :: [ByteString] -> ByteString
- isPrefixOf :: ByteString -> ByteString -> Bool
- isSuffixOf :: ByteString -> ByteString -> Bool
- elem :: Char -> ByteString -> Bool
- notElem :: Char -> ByteString -> Bool
- find :: (Char -> Bool) -> ByteString -> Maybe Char
- filter :: (Char -> Bool) -> ByteString -> ByteString
- partition :: (Char -> Bool) -> ByteString -> (ByteString, ByteString)
- index :: ByteString -> Int64 -> Char
- indexMaybe :: ByteString -> Int64 -> Maybe Char
- (!?) :: ByteString -> Int64 -> Maybe Char
- elemIndex :: Char -> ByteString -> Maybe Int64
- elemIndexEnd :: Char -> ByteString -> Maybe Int64
- elemIndices :: Char -> ByteString -> [Int64]
- findIndex :: (Char -> Bool) -> ByteString -> Maybe Int64
- findIndexEnd :: (Char -> Bool) -> ByteString -> Maybe Int64
- findIndices :: (Char -> Bool) -> ByteString -> [Int64]
- count :: Char -> ByteString -> Int64
- zip :: ByteString -> ByteString -> [(Char, Char)]
- zipWith :: (Char -> Char -> a) -> ByteString -> ByteString -> [a]
- packZipWith :: (Char -> Char -> Char) -> ByteString -> ByteString -> ByteString
- unzip :: [(Char, Char)] -> (ByteString, ByteString)
- copy :: ByteString -> ByteString
- readInt :: ByteString -> Maybe (Int, ByteString)
- readInteger :: ByteString -> Maybe (Integer, ByteString)
- getContents :: IO ByteString
- putStr :: ByteString -> IO ()
- putStrLn :: ByteString -> IO ()
- interact :: (ByteString -> ByteString) -> IO ()
- readFile :: FilePath -> IO ByteString
- writeFile :: FilePath -> ByteString -> IO ()
- appendFile :: FilePath -> ByteString -> IO ()
- 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 ()
- hPutStrLn :: Handle -> ByteString -> IO ()
The ByteString type
data ByteString Source #
A space-efficient representation of a Word8 vector, supporting many
efficient operations.
A lazy ByteString contains 8-bit bytes, or by using the operations
from Data.ByteString.Lazy.Char8 it can be interpreted as containing
8-bit characters.
Instances
Introducing and eliminating ByteStrings
empty :: ByteString Source #
O(1) The empty ByteString
singleton :: Char -> ByteString Source #
O(1) Convert a Char into a ByteString
pack :: [Char] -> ByteString Source #
O(n) Convert a String into a ByteString.
unpack :: ByteString -> [Char] Source #
O(n) Converts a ByteString to a String.
fromChunks :: [ByteString] -> ByteString Source #
O(c) Convert a list of strict ByteString into a lazy ByteString
toChunks :: ByteString -> [ByteString] Source #
O(c) Convert a lazy ByteString into a list of strict ByteString
fromStrict :: ByteString -> ByteString Source #
O(1) Convert a strict ByteString into a lazy ByteString.
toStrict :: ByteString -> ByteString Source #
O(n) Convert a lazy ByteString into a strict ByteString.
Note that this is an expensive operation that forces the whole lazy ByteString into memory and then copies all the data. If possible, try to avoid converting back and forth between strict and lazy bytestrings.
Basic interface
cons :: Char -> ByteString -> ByteString infixr 5 Source #
cons' :: Char -> ByteString -> ByteString infixr 5 Source #
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.
snoc :: ByteString -> Char -> ByteString infixl 5 Source #
O(n) Append a Char to the end of a ByteString. Similar to
cons, this function performs a memcpy.
append :: ByteString -> ByteString -> ByteString Source #
O(n/c) Append two ByteStrings
head :: ByteString -> Char Source #
O(1) Extract the first element of a ByteString, which must be non-empty.
uncons :: ByteString -> Maybe (Char, ByteString) Source #
O(1) Extract the head and tail of a ByteString, returning Nothing if it is empty.
last :: ByteString -> Char Source #
O(1) Extract the last element of a packed string, which must be non-empty.
tail :: HasCallStack => ByteString -> ByteString Source #
O(1) Extract the elements after the head of a ByteString, which must be non-empty.
This is a partial function, consider using uncons instead.
unsnoc :: ByteString -> Maybe (ByteString, Char) Source #
init :: HasCallStack => ByteString -> ByteString Source #
O(n/c) Returns all the elements of a ByteString except the last one.
This is a partial function, consider using unsnoc instead.
null :: ByteString -> Bool Source #
O(1) Test whether a ByteString is empty.
Transforming ByteStrings
map :: (Char -> Char) -> ByteString -> ByteString Source #
O(n) map f xs is the ByteString obtained by applying f to each element of xs
reverse :: ByteString -> ByteString Source #
O(n) reverse xs returns the elements of xs in reverse order.
intersperse :: Char -> ByteString -> ByteString Source #
O(n) The intersperse function takes a Char and a ByteString
and `intersperses' that Char between the elements of the
ByteString. It is analogous to the intersperse function on Lists.
intercalate :: ByteString -> [ByteString] -> ByteString Source #
O(n) The intercalate function takes a ByteString and a list of
ByteStrings and concatenates the list after interspersing the first
argument between each element of the list.
transpose :: [ByteString] -> [ByteString] Source #
The transpose function transposes the rows and columns of its
ByteString argument.
Reducing ByteStrings (folds)
foldl :: (a -> Char -> a) -> a -> ByteString -> a Source #
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 Source #
foldl' is like foldl, but strict in the accumulator.
foldl1 :: (Char -> Char -> Char) -> ByteString -> Char Source #
foldl1 is a variant of foldl that has no starting value
argument, and thus must be applied to non-empty ByteStrings.
foldr :: (Char -> a -> a) -> a -> ByteString -> a Source #
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 Source #
foldr1 :: (Char -> Char -> Char) -> ByteString -> Char Source #
foldr1 is a variant of foldr that has no starting value argument,
and thus must be applied to non-empty ByteStrings
Special folds
concat :: [ByteString] -> ByteString Source #
O(n) Concatenate a list of ByteStrings.
concatMap :: (Char -> ByteString) -> ByteString -> ByteString Source #
Map a function over a ByteString and concatenate the results
any :: (Char -> Bool) -> ByteString -> Bool Source #
Applied to a predicate and a ByteString, any determines if
any element of the ByteString satisfies the predicate.
all :: (Char -> Bool) -> ByteString -> Bool Source #
Applied to a predicate and a ByteString, all determines if
all elements of the ByteString satisfy the predicate.
maximum :: ByteString -> Char Source #
maximum returns the maximum value from a ByteString
minimum :: ByteString -> Char Source #
minimum returns the minimum value from a ByteString
compareLength :: ByteString -> Int64 -> Ordering Source #
O(c) compareLength compares the length of a ByteString
to an Int64
Since: bytestring-0.11.1.0
Building ByteStrings
Scans
scanl :: (Char -> Char -> Char) -> Char -> ByteString -> ByteString Source #
scanl1 :: (Char -> Char -> Char) -> ByteString -> ByteString Source #
Arguments
| :: (Char -> Char -> Char) | element -> accumulator -> new accumulator |
| -> Char | starting value of accumulator |
| -> ByteString | input of length n |
| -> ByteString | output of length n+1 |
scanr1 :: (Char -> Char -> Char) -> ByteString -> ByteString Source #
Accumulating maps
mapAccumL :: (acc -> Char -> (acc, Char)) -> acc -> ByteString -> (acc, ByteString) Source #
mapAccumR :: (acc -> Char -> (acc, Char)) -> acc -> ByteString -> (acc, ByteString) Source #
Infinite ByteStrings
repeat :: Char -> ByteString Source #
is an infinite ByteString, with repeat xx the value of every
element.
replicate :: Int64 -> Char -> ByteString Source #
O(n) is a ByteString of length replicate n xn with x
the value of every element.
cycle :: HasCallStack => ByteString -> ByteString Source #
cycle ties a finite ByteString into a circular one, or equivalently,
the infinite repetition of the original ByteString.
iterate :: (Char -> Char) -> Char -> ByteString Source #
returns an infinite ByteString of repeated applications
of iterate f xf to x:
iterate f x == [x, f x, f (f x), ...]
Unfolding ByteStrings
unfoldr :: (a -> Maybe (Char, a)) -> a -> ByteString Source #
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.
Substrings
Breaking strings
take :: Int64 -> ByteString -> ByteString Source #
takeEnd :: Int64 -> ByteString -> ByteString Source #
drop :: Int64 -> ByteString -> ByteString Source #
dropEnd :: Int64 -> ByteString -> ByteString Source #
splitAt :: Int64 -> ByteString -> (ByteString, ByteString) Source #
takeWhile :: (Char -> Bool) -> ByteString -> ByteString Source #
takeWhile, applied to a predicate p and a ByteString xs,
returns the longest prefix (possibly empty) of xs of elements that
satisfy p.
takeWhileEnd :: (Char -> Bool) -> ByteString -> ByteString Source #
Returns the longest (possibly empty) suffix of elements satisfying the predicate.
is equivalent to takeWhileEnd p.reverse . takeWhile p . reverse
Since: bytestring-0.11.2.0
dropWhile :: (Char -> Bool) -> ByteString -> ByteString Source #
dropWhileEnd :: (Char -> Bool) -> ByteString -> ByteString Source #
Similar to dropWhileEnd,
drops the longest (possibly empty) suffix of elements
satisfying the predicate and returns the remainder.
is equivalent to dropWhileEnd p.reverse . dropWhile p . reverse
Since: bytestring-0.11.2.0
span :: (Char -> Bool) -> ByteString -> (ByteString, ByteString) Source #
spanEnd :: (Char -> Bool) -> ByteString -> (ByteString, ByteString) Source #
spanEnd behaves like span but from the end of the ByteString.
We have
spanEnd (not.isSpace) "x y z" == ("x y ","z")and
spanEnd (not . isSpace) ps == let (x,y) = span (not.isSpace) (reverse ps) in (reverse y, reverse x)
Since: bytestring-0.11.2.0
break :: (Char -> Bool) -> ByteString -> (ByteString, ByteString) Source #
breakEnd :: (Char -> Bool) -> ByteString -> (ByteString, ByteString) Source #
breakEnd behaves like break but from the end of the ByteString
breakEnd p == spanEnd (not.p)
Since: bytestring-0.11.2.0
group :: ByteString -> [ByteString] Source #
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 string 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.
groupBy :: (Char -> Char -> Bool) -> ByteString -> [ByteString] Source #
inits :: ByteString -> [ByteString] Source #
Returns all initial segments of the given ByteString, shortest first.
tails :: ByteString -> [ByteString] Source #
O(n) Returns all final segments of the given ByteString, longest first.
initsNE :: ByteString -> NonEmpty ByteString Source #
Returns all initial segments of the given ByteString, shortest first.
Since: bytestring-0.11.4.0
tailsNE :: ByteString -> NonEmpty ByteString Source #
O(n) Returns all final segments of the given ByteString, longest first.
Since: bytestring-0.11.4.0
stripPrefix :: ByteString -> ByteString -> Maybe ByteString Source #
O(n) The stripPrefix function takes two ByteStrings and returns Just
the remainder of the second iff the first is its prefix, and otherwise
Nothing.
Since: bytestring-0.10.8.0
stripSuffix :: ByteString -> ByteString -> Maybe ByteString Source #
O(n) The stripSuffix function takes two ByteStrings and returns Just
the remainder of the second iff the first is its suffix, and otherwise
Nothing.
Breaking into many substrings
split :: Char -> ByteString -> [ByteString] Source #
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" == ["",""] split undefined "" == [] -- and not [""]
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.
splitWith :: (Char -> Bool) -> ByteString -> [ByteString] Source #
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 undefined "" == [] -- and not [""]
Breaking into lines and words
lines :: ByteString -> [ByteString] Source #
lines lazily splits a ByteString into a list of ByteStrings at
newline Chars ('\n'). The resulting strings do not contain newlines.
The first chunk of the result is only strict in the first chunk of the
input.
Note that it does not regard CR ('\r') as a newline character.
words :: ByteString -> [ByteString] Source #
words breaks a ByteString up into a list of words, which
were delimited by Chars representing white space. And
tokens isSpace = words
unlines :: [ByteString] -> ByteString Source #
unwords :: [ByteString] -> ByteString Source #
Predicates
isPrefixOf :: ByteString -> ByteString -> Bool Source #
O(n) The isPrefixOf function takes two ByteStrings and returns True
iff the first is a prefix of the second.
isSuffixOf :: ByteString -> ByteString -> Bool Source #
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
Searching ByteStrings
Searching by equality
elem :: Char -> ByteString -> Bool Source #
O(n) elem is the ByteString membership predicate. This
implementation uses memchr(3).
Searching with a predicate
filter :: (Char -> Bool) -> ByteString -> ByteString Source #
O(n) filter, applied to a predicate and a ByteString,
returns a ByteString containing those characters that satisfy the
predicate.
partition :: (Char -> Bool) -> ByteString -> (ByteString, ByteString) Source #
Since: bytestring-0.10.12.0
Indexing ByteStrings
index :: ByteString -> Int64 -> Char Source #
O(1) ByteString index (subscript) operator, starting from 0.
indexMaybe :: ByteString -> Int64 -> Maybe Char Source #
O(1) ByteString index, starting from 0, that returns Just if:
0 <= n < length bs
Since: bytestring-0.11.0.0
(!?) :: ByteString -> Int64 -> Maybe Char Source #
O(1) ByteString index, starting from 0, that returns Just if:
0 <= n < length bs
Since: bytestring-0.11.0.0
elemIndex :: Char -> ByteString -> Maybe Int64 Source #
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.
elemIndexEnd :: Char -> ByteString -> Maybe Int64 Source #
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 = case elemIndex c (reverse xs) of Nothing -> Nothing Just i -> Just (length xs - 1 - i)
Since: bytestring-0.11.1.0
elemIndices :: Char -> ByteString -> [Int64] Source #
O(n) The elemIndices function extends elemIndex, by returning
the indices of all elements equal to the query element, in ascending order.
findIndex :: (Char -> Bool) -> ByteString -> Maybe Int64 Source #
The findIndex function takes a predicate and a ByteString and
returns the index of the first element in the ByteString satisfying the predicate.
findIndexEnd :: (Char -> Bool) -> ByteString -> Maybe Int64 Source #
The findIndexEnd function takes a predicate and a ByteString and
returns the index of the last element in the ByteString
satisfying the predicate.
Since: bytestring-0.11.1.0
findIndices :: (Char -> Bool) -> ByteString -> [Int64] Source #
The findIndices function extends findIndex, by returning the
indices of all elements satisfying the predicate, in ascending order.
count :: Char -> ByteString -> Int64 Source #
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.
Zipping and unzipping ByteStrings
zip :: ByteString -> ByteString -> [(Char, Char)] Source #
zipWith :: (Char -> Char -> a) -> ByteString -> ByteString -> [a] Source #
packZipWith :: (Char -> Char -> Char) -> ByteString -> ByteString -> ByteString Source #
A specialised version of zipWith for the common case of a
simultaneous map over two ByteStrings, to build a 3rd.
Since: bytestring-0.11.1.0
unzip :: [(Char, Char)] -> (ByteString, ByteString) Source #
Ordered ByteStrings
Low level conversions
Copying ByteStrings
copy :: ByteString -> ByteString Source #
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.
Reading from ByteStrings
readInt :: ByteString -> Maybe (Int, ByteString) Source #
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.
Note: This function will overflow the Int for large integers.
readInteger :: ByteString -> Maybe (Integer, ByteString) Source #
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.
I/O with ByteStrings
ByteString I/O uses binary mode, without any character decoding or newline conversion. The fact that it does not respect the Handle newline mode is considered a flaw and may be changed in a future version.
Standard input and output
getContents :: IO ByteString Source #
getContents. Equivalent to hGetContents stdin. Will read lazily
putStr :: ByteString -> IO () Source #
putStrLn :: ByteString -> IO () Source #
interact :: (ByteString -> ByteString) -> IO () Source #
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.
Files
readFile :: FilePath -> IO ByteString Source #
Read an entire file lazily into a ByteString.
The Handle will be held open until EOF is encountered.
Note that this function's implementation relies on hGetContents.
The reader is advised to read its documentation.
writeFile :: FilePath -> ByteString -> IO () Source #
Write a ByteString to a file.
appendFile :: FilePath -> ByteString -> IO () Source #
Append a ByteString to a file.
I/O with Handles
hGetContents :: Handle -> IO ByteString Source #
Read entire handle contents lazily into a ByteString. Chunks
are read on demand, using the default chunk size.
File handles are closed on EOF if all the file is read, or through garbage collection otherwise.
hGet :: Handle -> Int -> IO ByteString Source #
Read n bytes into a ByteString, directly from the specified Handle.
hGetNonBlocking :: Handle -> Int -> IO ByteString Source #
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.
hPut :: Handle -> ByteString -> IO () Source #
Outputs a ByteString to the specified Handle.
The chunks will be
written one at a time. Other threads might write to the Handle in between,
and hence hPut alone is not suitable for concurrent writes.
hPutNonBlocking :: Handle -> ByteString -> IO ByteString Source #
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.