ByteString

ByteString

data ByteString

A space-efficient representation of a Word8 vector, supporting many efficient operations.

A ByteString contains 8-bit bytes, or by using the operations from Data.ByteString.Char8 it can be interpreted as containing 8-bit characters.

Instances

Eq ByteString

Defined in Data.ByteString.Internal

Methods

(==) :: ByteString -> ByteString -> Bool

(/=) :: ByteString -> ByteString -> Bool

Data ByteString

Defined in Data.ByteString.Internal

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> ByteString -> c ByteString

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c ByteString

toConstr :: ByteString -> Constr

dataTypeOf :: ByteString -> DataType

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c ByteString)

dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c ByteString)

gmapT :: (forall b. Data b => b -> b) -> ByteString -> ByteString

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> ByteString -> r

gmapQr :: (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> ByteString -> r

gmapQ :: (forall d. Data d => d -> u) -> ByteString -> [u]

gmapQi :: Int -> (forall d. Data d => d -> u) -> ByteString -> u

gmapM :: Monad m => (forall d. Data d => d -> m d) -> ByteString -> m ByteString

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> ByteString -> m ByteString

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> ByteString -> m ByteString

Ord ByteString

Defined in Data.ByteString.Internal

Methods

compare :: ByteString -> ByteString -> Ordering

(<) :: ByteString -> ByteString -> Bool

(<=) :: ByteString -> ByteString -> Bool

(>) :: ByteString -> ByteString -> Bool

(>=) :: ByteString -> ByteString -> Bool

max :: ByteString -> ByteString -> ByteString

min :: ByteString -> ByteString -> ByteString

Read ByteString

Defined in Data.ByteString.Internal

Methods

readsPrec :: Int -> ReadS ByteString

readList :: ReadS [ByteString]

readPrec :: ReadPrec ByteString

readListPrec :: ReadPrec [ByteString]

Show ByteString

Defined in Data.ByteString.Internal

Methods

showsPrec :: Int -> ByteString -> ShowS

show :: ByteString -> String

showList :: [ByteString] -> ShowS

IsString ByteString

Defined in Data.ByteString.Internal

Methods

fromString :: String -> ByteString

Semigroup ByteString

Defined in Data.ByteString.Internal

Methods

(<>) :: ByteString -> ByteString -> ByteString

sconcat :: NonEmpty ByteString -> ByteString

stimes :: Integral b => b -> ByteString -> ByteString

Monoid ByteString

Defined in Data.ByteString.Internal

Methods

mempty :: ByteString

mappend :: ByteString -> ByteString -> ByteString

mconcat :: [ByteString] -> ByteString

Hashable ByteString

Defined in Data.Hashable.Class

Methods

hashWithSalt :: Int -> ByteString -> Int

hash :: ByteString -> Int

FoldCase ByteString

Note that foldCase on ByteStrings is only guaranteed to be correct for ISO-8859-1 encoded strings!

Defined in Data.CaseInsensitive.Internal

Methods

foldCase :: ByteString -> ByteString

foldCaseList :: [ByteString] -> [ByteString]

NFData ByteString

Defined in Data.ByteString.Internal

Methods

rnf :: ByteString -> ()

IsByteString ByteString

Defined in Data.ByteString.Lens

Methods

packedBytes :: Iso' [Word8] ByteString

packedChars :: Iso' String ByteString

bytes :: IndexedTraversal' Int ByteString Word8

chars :: IndexedTraversal' Int ByteString Char

Ixed ByteString

Defined in Control.Lens.At

Methods

ix :: Index ByteString -> Traversal' ByteString (IxValue ByteString)

AsEmpty ByteString

Defined in Control.Lens.Empty

Methods

_Empty :: Prism' ByteString ()

Reversing ByteString

Defined in Control.Lens.Internal.Iso

Methods

reversing :: ByteString -> ByteString

AsNumber ByteString

Defined in Data.Aeson.Lens

Methods

_Number :: Prism' ByteString Scientific

_Double :: Prism' ByteString Double

_Integer :: Prism' ByteString Integer

AsPrimitive ByteString

Defined in Data.Aeson.Lens

Methods

_Primitive :: Prism' ByteString Primitive

_String :: Prism' ByteString Text

_Bool :: Prism' ByteString Bool

_Null :: Prism' ByteString ()

AsValue ByteString

Defined in Data.Aeson.Lens

Methods

_Value :: Prism' ByteString Value

_Object :: Prism' ByteString (HashMap Text Value)

_Array :: Prism' ByteString (Vector Value)

AsJSON ByteString

Defined in Data.Aeson.Lens

Methods

_JSON :: (FromJSON a, ToJSON a) => Prism' ByteString a

Stream ByteString

Defined in Text.Megaparsec.Stream

Associated Types

type Token ByteString :: *

type Tokens ByteString :: *

Methods

tokenToChunk :: Proxy ByteString -> Token ByteString -> Tokens ByteString

tokensToChunk :: Proxy ByteString -> [Token ByteString] -> Tokens ByteString

chunkToTokens :: Proxy ByteString -> Tokens ByteString -> [Token ByteString]

chunkLength :: Proxy ByteString -> Tokens ByteString -> Int

chunkEmpty :: Proxy ByteString -> Tokens ByteString -> Bool

positionAt1 :: Proxy ByteString -> SourcePos -> Token ByteString -> SourcePos

positionAtN :: Proxy ByteString -> SourcePos -> Tokens ByteString -> SourcePos

advance1 :: Proxy ByteString -> Pos -> SourcePos -> Token ByteString -> SourcePos

advanceN :: Proxy ByteString -> Pos -> SourcePos -> Tokens ByteString -> SourcePos

take1_ :: ByteString -> Maybe (Token ByteString, ByteString)

takeN_ :: Int -> ByteString -> Maybe (Tokens ByteString, ByteString)

takeWhile_ :: (Token ByteString -> Bool) -> ByteString -> (Tokens ByteString, ByteString)

Serialise ByteString

Since: serialise-0.2.0.0

Defined in Codec.Serialise.Class

Methods

encode :: ByteString -> Encoding

decode :: Decoder s ByteString

encodeList :: [ByteString] -> Encoding

decodeList :: Decoder s [ByteString]

Substitution ByteString

Defined in Data.ByteString.Search.Substitution

Methods

substitution :: ByteString -> [ByteString] -> [ByteString]

prependCycle :: ByteString -> ByteString0 -> ByteString0

Strict ByteString ByteString

Defined in Control.Lens.Iso

Methods

strict :: Iso' ByteString ByteString0

(a ~ Word8, b ~ Word8) => Each ByteString ByteString a b

each :: Traversal ByteString ByteString Word8 Word8

Defined in Control.Lens.Each

Methods

each :: Traversal ByteString ByteString a b

Cons ByteString ByteString Word8 Word8

Defined in Control.Lens.Cons

Methods

_Cons :: Prism ByteString ByteString (Word8, ByteString) (Word8, ByteString)

Snoc ByteString ByteString Word8 Word8

Defined in Control.Lens.Cons

Methods

_Snoc :: Prism ByteString ByteString (ByteString, Word8) (ByteString, Word8)

type Index ByteString

Defined in Control.Lens.At

type Index ByteString = Int

type IxValue ByteString

Defined in Control.Lens.At

type IxValue ByteString = Word8

type Tokens ByteString

Defined in Text.Megaparsec.Stream

type Tokens ByteString = ByteString

type Token ByteString

Defined in Text.Megaparsec.Stream

type Token ByteString = Word8

all :: (Word8 -> Bool) -> ByteString -> Bool

O(n) Applied to a predicate and a ByteString, all determines if all elements of the ByteString satisfy the predicate.

any :: (Word8 -> Bool) -> ByteString -> Bool

O(n) Applied to a predicate and a ByteString, any determines if any element of the ByteString satisfies the predicate.

asHexadecimal :: ByteString -> ByteString

Convert a bitvector into a lower-case ASCII hexadecimal string. This is helpful for visualizing raw binary data, rather than for parsing as such.

break :: (Word8 -> Bool) -> ByteString -> (ByteString, ByteString)

break p is equivalent to span (not . p).

Under GHC, a rewrite rule will transform break (==) into a call to the specialised breakByte:

break ((==) x) = breakByte x
break (==x) = breakByte x

breakAfter

Arguments

:: ByteString

String to search for

-> ByteString

String to search in

-> (ByteString, ByteString)

Head and tail of string broken after substring

breakAfter pattern target splits target behind the first occurrence of pattern. An empty second component means that either the pattern does not occur in the target or the first occurrence of pattern is at the very end of target. To discriminate between those cases, use e.g. isSuffixOf.

  uncurry append . breakAfter pattern = id

breakEnd :: (Word8 -> Bool) -> ByteString -> (ByteString, ByteString)

breakEnd behaves like break but from the end of the ByteString

breakEnd p == spanEnd (not.p)

breakOn

Arguments

:: ByteString

String to search for

-> ByteString

String to search in

-> (ByteString, ByteString)

Head and tail of string broken at substring

breakOn pattern target splits target at the first occurrence of pattern. If the pattern does not occur in the target, the second component of the result is empty, otherwise it starts with pattern. If the pattern is empty, the first component is empty.

  uncurry append . breakOn pattern = id

breakSubstring

Arguments

:: ByteString

String to search for

-> ByteString

String to search in

-> (ByteString, ByteString)

Head and tail of string broken at substring

Break a string on a substring, returning a pair of the part of the string prior to the match, and the rest of the string.

The following relationships hold:

break (== c) l == breakSubstring (singleton c) l

and:

findSubstring s l ==
   if null s then Just 0
             else case breakSubstring s l of
                      (x,y) | null y    -> Nothing
                            | otherwise -> Just (length x)

For example, to tokenise a string, dropping delimiters:

tokenise x y = h : if null t then [] else tokenise x (drop (length x) t)
    where (h,t) = breakSubstring x y

To skip to the first occurence of a string:

snd (breakSubstring x y)

To take the parts of a string before a delimiter:

fst (breakSubstring x y)

Note that calling `breakSubstring x` does some preprocessing work, so you should avoid unnecessarily duplicating breakSubstring calls with the same pattern.

concat :: [ByteString] -> ByteString

O(n) Concatenate a list of ByteStrings.

concatMap :: (Word8 -> ByteString) -> ByteString -> ByteString

Map a function over a ByteString and concatenate the results

copy :: ByteString -> ByteString

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.

count :: Word8 -> ByteString -> Int

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.

drop :: Int -> ByteString -> ByteString

O(1) drop n xs returns the suffix of xs after the first n elements, or [] if n > length xs.

dropWhile :: (Word8 -> Bool) -> ByteString -> ByteString

dropWhile p xs returns the suffix remaining after takeWhile p xs.

elem :: Word8 -> ByteString -> Bool

O(n) elem is the ByteString membership predicate.

elemIndex :: Word8 -> ByteString -> Maybe Int

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).

elemIndexEnd :: Word8 -> ByteString -> Maybe Int

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)

elemIndices :: Word8 -> ByteString -> [Int]

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).

filter :: (Word8 -> Bool) -> ByteString -> ByteString

O(n) filter, applied to a predicate and a ByteString, returns a ByteString containing those characters that satisfy the predicate.

find :: (Word8 -> Bool) -> ByteString -> Maybe Word8

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

findIndex :: (Word8 -> Bool) -> ByteString -> Maybe Int

The findIndex function takes a predicate and a ByteString and returns the index of the first element in the ByteString satisfying the predicate.

findIndices :: (Word8 -> Bool) -> ByteString -> [Int]

The findIndices function extends findIndex, by returning the indices of all elements satisfying the predicate, in ascending order.

foldl' :: (a -> Word8 -> a) -> a -> ByteString -> a

foldl' is like foldl, but strict in the accumulator.

foldr :: (Word8 -> a -> a) -> a -> ByteString -> a

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.

group :: ByteString -> [ByteString]

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. It is about 40% faster than groupBy (==)

groupBy :: (Word8 -> Word8 -> Bool) -> ByteString -> [ByteString]

The groupBy function is the non-overloaded version of group.

index :: ByteString -> Int -> Word8

O(1) ByteString index (subscript) operator, starting from 0.

indices

Arguments

:: ByteString

Pattern to find

-> ByteString

String to search

-> [Int]

Offsets of matches

indices finds the starting indices of all possibly overlapping occurrences of the pattern in the target string. If the pattern is empty, the result is [0 .. length target].

In general, not . null $ indices pat target is a much more efficient version of isInfixOf.

inits :: ByteString -> [ByteString]

O(n) Return all initial segments of the given ByteString, shortest first.

intercalate :: ByteString -> [ByteString] -> ByteString

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.

intersperse :: Word8 -> ByteString -> ByteString

O(n) 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.

isInfixOf :: ByteString -> ByteString -> Bool

Check whether one string is a substring of another. isInfixOf p s is equivalent to not (null (findSubstrings p s)).

isPrefixOf :: ByteString -> ByteString -> Bool

O(n) The isPrefixOf function takes two ByteStrings and returns True if the first is a prefix of the second.

isSuffixOf :: ByteString -> ByteString -> Bool

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

However, the real implemenation uses memcmp to compare the end of the string only, with no reverse required..

length :: ByteString -> Int

O(1) length returns the length of a ByteString as an Int.

map :: (Word8 -> Word8) -> ByteString -> ByteString

O(n) map f xs is the ByteString obtained by applying f to each element of xs.

mapAccumL :: (acc -> Word8 -> (acc, Word8)) -> acc -> ByteString -> (acc, ByteString)

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 list.

mapAccumR :: (acc -> Word8 -> (acc, Word8)) -> acc -> ByteString -> (acc, ByteString)

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.

nonOverlappingIndices

Arguments

:: ByteString

Pattern to find

-> ByteString

String to search

-> [Int]

Offsets of matches

nonOverlappingIndices finds the starting indices of all non-overlapping occurrences of the pattern in the target string. It is more efficient than removing indices from the list produced by indices.

notElem :: Word8 -> ByteString -> Bool

O(n) notElem is the inverse of elem

null :: ByteString -> Bool

O(1) Test whether a ByteString is empty.

pack :: [Word8] -> ByteString

O(n) Convert a [Word8] into a ByteString.

For applications with large numbers of string literals, pack can be a bottleneck. In such cases, consider using packAddress (GHC only).

packCString :: CString -> IO ByteString

O(n). Construct a new ByteString from a CString. The resulting ByteString is an immutable copy of the original CString, and is managed on the Haskell heap. The original CString must be null terminated.

packCStringLen :: CStringLen -> IO ByteString

O(n). Construct a new ByteString from a CStringLen. The resulting ByteString is an immutable copy of the original CStringLen. The ByteString is a normal Haskell value and will be managed on the Haskell heap.

partition :: (Word8 -> Bool) -> ByteString -> (ByteString, ByteString)

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)

random

Arguments

:: Natural

Length of the result bytestring in bytes

-> IO ByteString

Generate a random bytestring of length n. The PRNG is seeded from the system randomness source.

ioProperty $ ((fromIntegral n ===) . B.length) <$> random n

n > 4 ==> ioProperty $ (/=) <$> random n <*> random n

replace

Arguments

:: Substitution rep

=> ByteString

Substring to replace

-> rep

Replacement string

-> ByteString

String to modify

-> ByteString

Lazy result

replace pat sub text replaces all (non-overlapping) occurrences of pat in text with sub. If occurrences of pat overlap, the first occurrence that does not overlap with a replaced previous occurrence is substituted. Occurrences of pat arising from a substitution will not be substituted. For example:

  replace "ana" "olog" "banana" = "bologna"
  replace "ana" "o" "bananana" = "bono"
  replace "aab" "abaa" "aaabb" = "aabaab"

The result is a lazy ByteString, which is lazily produced, without copying. Equality of pattern and substitution is not checked, but

  (concat . toChunks $ replace pat pat text) == text

holds. If the pattern is empty but not the substitution, the result is equivalent to (were they Strings) cycle sub.

For non-empty pat and sub a strict ByteString,

  fromChunks . intersperse sub . split pat = replace pat sub

and analogous relations hold for other types of sub.

replicate :: Int -> Word8 -> ByteString

O(n) replicate n x is a ByteString of length n with x the value of every element. The following holds:

replicate w c = unfoldr w (\u -> Just (u,u)) c

This implemenation uses memset(3)

reverse :: ByteString -> ByteString

O(n) reverse xs efficiently returns the elements of xs in reverse order.

scanl :: (Word8 -> Word8 -> Word8) -> Word8 -> ByteString -> ByteString

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.

scanl1 :: (Word8 -> Word8 -> Word8) -> ByteString -> ByteString

scanl1 is a variant of scanl that has no starting value argument. This function will fuse.

scanl1 f [x1, x2, ...] == [x1, x1 `f` x2, ...]

scanr :: (Word8 -> Word8 -> Word8) -> Word8 -> ByteString -> ByteString

scanr is the right-to-left dual of scanl.

scanr1 :: (Word8 -> Word8 -> Word8) -> ByteString -> ByteString

scanr1 is a variant of scanr that has no starting value argument.

singleton :: Word8 -> ByteString

O(1) Convert a Word8 into a ByteString

snoc :: ByteString -> Word8 -> ByteString infixl 5

O(n) Append a byte to the end of a ByteString

sort :: ByteString -> ByteString

O(n) Sort a ByteString efficiently, using counting sort.

span :: (Word8 -> Bool) -> ByteString -> (ByteString, ByteString)

span p xs breaks the ByteString into two segments. It is equivalent to (takeWhile p xs, dropWhile p xs)

spanEnd :: (Word8 -> Bool) -> ByteString -> (ByteString, ByteString)

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)

split

Arguments

:: ByteString

Pattern to split on

-> ByteString

String to split

-> [ByteString]

Fragments of string

split pattern target splits target at each (non-overlapping) occurrence of pattern, removing pattern. If pattern is empty, the result is an infinite list of empty ByteStrings, if target is empty but not pattern, the result is an empty list, otherwise the following relations hold:

  concat . intersperse pat . split pat = id,
  length (split pattern target) ==
              length (nonOverlappingIndices pattern target) + 1,

no fragment in the result contains an occurrence of pattern.

splitAt :: Int -> ByteString -> (ByteString, ByteString)

O(1) splitAt n xs is equivalent to (take n xs, drop n xs).

splitKeepEnd

Arguments

:: ByteString

Pattern to split on

-> ByteString

String to split

-> [ByteString]

Fragments of string

splitKeepEnd pattern target splits target after each (non-overlapping) occurrence of pattern. If pattern is empty, the result is an infinite list of empty ByteStrings, otherwise the following relations hold:

  concat . splitKeepEnd pattern = id,

all fragments in the result except possibly the last end with pattern, no fragment contains more than one occurrence of pattern.

splitKeepFront

Arguments

:: ByteString

Pattern to split on

-> ByteString

String to split

-> [ByteString]

Fragments of string

splitKeepFront is like splitKeepEnd, except that target is split before each occurrence of pattern and hence all fragments with the possible exception of the first begin with pattern. No fragment contains more than one non-overlapping occurrence of pattern.

splitWith :: (Word8 -> Bool) -> ByteString -> [ByteString]

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') []        == []

stripPrefix :: ByteString -> ByteString -> Maybe ByteString

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

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.

tails :: ByteString -> [ByteString]

O(n) Return all final segments of the given ByteString, longest first.

take :: Int -> ByteString -> ByteString

O(1) take n, applied to a ByteString xs, returns the prefix of xs of length n, or xs itself if n > length xs.

takeWhile :: (Word8 -> Bool) -> ByteString -> ByteString

takeWhile, applied to a predicate p and a ByteString xs, returns the longest prefix (possibly empty) of xs of elements that satisfy p.

transpose :: [ByteString] -> [ByteString]

The transpose function transposes the rows and columns of its ByteString argument.

uncons :: ByteString -> Maybe (Word8, ByteString)

O(1) Extract the head and tail of a ByteString, returning Nothing if it is empty.

unfoldr :: (a -> Maybe (Word8, a)) -> a -> ByteString

O(n), where n is the length of the result. 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 the next byte in the string, and b is the seed value for further production.

Examples:

   unfoldr (\x -> if x <= 5 then Just (x, x + 1) else Nothing) 0
== pack [0, 1, 2, 3, 4, 5]

unfoldrN :: Int -> (a -> Maybe (Word8, a)) -> a -> (ByteString, Maybe a)

O(n) Like unfoldr, unfoldrN builds a ByteString from a seed value. However, the length of the result is limited by the first argument to unfoldrN. This function is more efficient than unfoldr when the maximum length of the result is known.

The following equation relates unfoldrN and unfoldr:

fst (unfoldrN n f s) == take n (unfoldr f s)

unpack :: ByteString -> [Word8]

O(n) Converts a ByteString to a [Word8].

unsnoc :: ByteString -> Maybe (ByteString, Word8)

O(1) Extract the init and last of a ByteString, returning Nothing if it is empty.

unzip :: [(Word8, Word8)] -> (ByteString, ByteString)

O(n) unzip transforms a list of pairs of bytes into a pair of ByteStrings. Note that this performs two pack operations.

useAsCString :: ByteString -> (CString -> IO a) -> IO a

O(n) construction Use a ByteString with a function requiring a null-terminated CString. The CString is a copy and will be freed automatically; it must not be stored or used after the subcomputation finishes.

useAsCStringLen :: ByteString -> (CStringLen -> IO a) -> IO a

O(n) construction Use a ByteString with a function requiring a CStringLen. As for useAsCString this function makes a copy of the original ByteString. It must not be stored or used after the subcomputation finishes.

zip :: ByteString -> ByteString -> [(Word8, Word8)]

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.

zipWith :: (Word8 -> Word8 -> a) -> ByteString -> ByteString -> [a]

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.

Optics

bytes :: IsByteString t => IndexedTraversal' Int t Word8

Traverse each Word8 in a strict or lazy ByteString

This Traversal walks each strict ByteString chunk in a tree-like fashion enable zippers to seek to locations more quickly and accelerate many monoidal queries, but up to associativity (and constant factors) it is equivalent to the much slower:

bytes ≡ unpackedBytes . traversed

anyOf bytes (== 0x80) :: ByteString -> Bool

packedBytes :: IsByteString t => Iso' [Word8] t

pack (or unpack) a list of bytes into a strict or lazy ByteString.

pack x ≡ x ^. packedBytes
unpack x ≡ x ^. from packedBytes
packedBytes ≡ from unpackedBytes

unpackedBytes :: IsByteString t => Iso' t [Word8]

unpack (or pack) a ByteString into a list of bytes

unpackedBytes ≡ from packedBytes
unpack x ≡ x ^. unpackedBytes
pack x ≡  x ^. from unpackedBytes

unpackedBytes :: Iso' ByteString [Word8]
unpackedBytes :: Iso' ByteString [Word8]