rio-0.1.22.0: A standard library for Haskell

Safe Haskell | None
Language | Haskell2010

RIO.ByteString.Lazy

Contents

- The `ByteString` type
- Introducing and eliminating `ByteString`s
- Basic interface
- Transforming ByteStrings
- Reducing `ByteString`s (folds)
  - Special folds
- Building ByteStrings
  - Scans
  - Accumulating maps
  - Infinite ByteStrings
  - Unfolding ByteStrings
- Substrings
  - Breaking strings
  - Breaking into many substrings
- Predicates
- Search ByteStrings
  - Searching by equality
  - Searching with a predicate
- Indexing ByteStrings
- Zipping and unzipping ByteStrings
- Low level conversions
  - Copying ByteStrings
- I/O with `ByteString`s
  - Standard input and output
  - Files
  - I/O with Handles

Description

Lazy `ByteString`. Import as:

    import qualified RIO.ByteString.Lazy as BL

This module does not export any partial functions. For those, see RIO.ByteString.Lazy.Partial

Synopsis

- data ByteString
- empty :: ByteString
- singleton :: Word8 -> ByteString
- pack :: [Word8] -> ByteString
- unpack :: ByteString -> [Word8]
- fromStrict :: StrictByteString -> LazyByteString
- toStrict :: LazyByteString -> StrictByteString
- fromChunks :: [StrictByteString] -> LazyByteString
- toChunks :: LazyByteString -> [StrictByteString]
- foldrChunks :: (StrictByteString -> a -> a) -> a -> ByteString -> a
- foldlChunks :: (a -> StrictByteString -> a) -> a -> ByteString -> a
- cons :: Word8 -> ByteString -> ByteString
- cons' :: Word8 -> ByteString -> ByteString
- snoc :: ByteString -> Word8 -> ByteString
- append :: ByteString -> ByteString -> ByteString
- uncons :: ByteString -> Maybe (Word8, ByteString)
- unsnoc :: ByteString -> Maybe (ByteString, Word8)
- null :: ByteString -> Bool
- length :: ByteString -> Int64
- map :: (Word8 -> Word8) -> ByteString -> ByteString
- reverse :: ByteString -> ByteString
- intersperse :: Word8 -> ByteString -> ByteString
- intercalate :: ByteString -> [ByteString] -> ByteString
- transpose :: [ByteString] -> [ByteString]
- foldl :: (a -> Word8 -> a) -> a -> ByteString -> a
- foldl' :: (a -> Word8 -> a) -> a -> ByteString -> a
- foldr :: (Word8 -> a -> a) -> a -> ByteString -> a
- concat :: [ByteString] -> ByteString
- concatMap :: (Word8 -> ByteString) -> ByteString -> ByteString
- any :: (Word8 -> Bool) -> ByteString -> Bool
- all :: (Word8 -> Bool) -> ByteString -> Bool
- scanl :: (Word8 -> Word8 -> Word8) -> Word8 -> ByteString -> ByteString
- mapAccumL :: (acc -> Word8 -> (acc, Word8)) -> acc -> ByteString -> (acc, ByteString)
- mapAccumR :: (acc -> Word8 -> (acc, Word8)) -> acc -> ByteString -> (acc, ByteString)
- repeat :: Word8 -> ByteString
- replicate :: Int64 -> Word8 -> ByteString
- cycle :: HasCallStack => ByteString -> ByteString
- iterate :: (Word8 -> Word8) -> Word8 -> ByteString
- unfoldr :: (a -> Maybe (Word8, a)) -> a -> ByteString
- 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]
- stripPrefix :: ByteString -> ByteString -> Maybe ByteString
- stripSuffix :: ByteString -> ByteString -> Maybe ByteString
- split :: Word8 -> ByteString -> [ByteString]
- splitWith :: (Word8 -> Bool) -> ByteString -> [ByteString]
- isPrefixOf :: ByteString -> ByteString -> Bool
- isSuffixOf :: ByteString -> ByteString -> Bool
- elem :: Word8 -> ByteString -> Bool
- notElem :: Word8 -> ByteString -> Bool
- find :: (Word8 -> Bool) -> ByteString -> Maybe Word8
- filter :: (Word8 -> Bool) -> ByteString -> ByteString
- partition :: (Word8 -> Bool) -> ByteString -> (ByteString, ByteString)
- index :: HasCallStack => ByteString -> Int64 -> Word8
- elemIndex :: Word8 -> ByteString -> Maybe Int64
- elemIndexEnd :: Word8 -> ByteString -> Maybe Int64
- elemIndices :: Word8 -> ByteString -> [Int64]
- findIndex :: (Word8 -> Bool) -> ByteString -> Maybe Int64
- findIndices :: (Word8 -> Bool) -> ByteString -> [Int64]
- count :: Word8 -> ByteString -> Int64
- zip :: ByteString -> ByteString -> [(Word8, Word8)]
- zipWith :: (Word8 -> Word8 -> a) -> ByteString -> ByteString -> [a]
- unzip :: [(Word8, Word8)] -> (ByteString, ByteString)
- copy :: ByteString -> ByteString
- getContents :: MonadIO m => m LByteString
- putStr :: MonadIO m => LByteString -> m ()
- putStrLn :: MonadIO m => LByteString -> m ()
- interact :: MonadIO m => (LByteString -> LByteString) -> m ()
- readFile :: MonadIO m => FilePath -> m LByteString
- writeFile :: MonadIO m => FilePath -> LByteString -> m ()
- appendFile :: MonadIO m => FilePath -> LByteString -> m ()
- hGetContents :: MonadIO m => Handle -> m LByteString
- hGet :: MonadIO m => Handle -> Int -> m LByteString
- hGetNonBlocking :: MonadIO m => Handle -> Int -> m LByteString
- hPut :: MonadIO m => Handle -> LByteString -> m ()
- hPutNonBlocking :: MonadIO m => Handle -> LByteString -> m LByteString
- hPutStr :: MonadIO m => Handle -> LByteString -> m ()

# The `ByteString` type

data ByteString #

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

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

#### Instances

Instances details

Data ByteString |
Instance details Defined in Data.ByteString.Lazy.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 :: forall r r'. (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 #
IsString ByteString | Beware: `fromString` truncates multi-byte characters to octets. e.g. "枯朶に烏のとまりけり秋の暮" becomes �6k�nh~�Q��n�
Instance details Defined in Data.ByteString.Lazy.Internal Methods fromString :: String -> ByteString #
Monoid ByteString |
Instance details Defined in Data.ByteString.Lazy.Internal Methods mempty :: ByteString # mappend :: ByteString -> ByteString -> ByteString # mconcat :: [ByteString] -> ByteString #
Semigroup ByteString |
Instance details Defined in Data.ByteString.Lazy.Internal Methods (<>) :: ByteString -> ByteString -> ByteString # sconcat :: NonEmpty ByteString -> ByteString # stimes :: Integral b => b -> ByteString -> ByteString #
IsList ByteString | Since: bytestring-0.10.12.0
Instance details Defined in Data.ByteString.Lazy.Internal Associated Types
type Item ByteString |
Instance details Defined in Data.ByteString.Lazy.Internal type Item ByteString = Word8
Methods fromList :: [Item ByteString] -> ByteString # fromListN :: Int -> [Item ByteString] -> ByteString # toList :: ByteString -> [Item ByteString] #
Read ByteString |
Instance details Defined in Data.ByteString.Lazy.Internal Methods readsPrec :: Int -> ReadS ByteString # readList :: ReadS [ByteString] # readPrec :: ReadPrec ByteString # readListPrec :: ReadPrec [ByteString] #
Show ByteString |
Instance details Defined in Data.ByteString.Lazy.Internal Methods showsPrec :: Int -> ByteString -> ShowS # show :: ByteString -> String # showList :: [ByteString] -> ShowS #
NFData ByteString |
Instance details Defined in Data.ByteString.Lazy.Internal Methods rnf :: ByteString -> () #
Eq ByteString |
Instance details Defined in Data.ByteString.Lazy.Internal Methods (==) :: ByteString -> ByteString -> Bool # (/=) :: ByteString -> ByteString -> Bool #
Ord ByteString |
Instance details Defined in Data.ByteString.Lazy.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 #
Hashable ByteString |
Instance details Defined in Data.Hashable.Class Methods hashWithSalt :: Int -> ByteString -> Int # hash :: ByteString -> Int #
Lift ByteString |
Instance details Defined in Data.ByteString.Lazy.Internal Methods lift :: Quote m => ByteString -> m Exp # liftTyped :: forall (m :: Type -> Type). Quote m => ByteString -> Code m ByteString #
type Item ByteString |
Instance details Defined in Data.ByteString.Lazy.Internal type Item ByteString = Word8

# Introducing and eliminating `ByteString`s

empty :: ByteString #

O(1) The empty `ByteString`

singleton :: Word8 -> ByteString #

O(1) Convert a `Word8` into a `ByteString`

pack :: [Word8] -> ByteString #

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

unpack :: ByteString -> [Word8] #

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

fromStrict :: StrictByteString -> LazyByteString #

O(1) Convert a `StrictByteString` into a `LazyByteString`.

toStrict :: LazyByteString -> StrictByteString #

O(n) Convert a `LazyByteString` into a `StrictByteString`.

Note that this is an expensive operation that forces the whole `LazyByteString` into memory and then copies all the data. If possible, try to avoid converting back and forth between strict and lazy bytestrings.

fromChunks :: [StrictByteString] -> LazyByteString #

O(c) Convert a list of `StrictByteString` into a `LazyByteString`

toChunks :: LazyByteString -> [StrictByteString] #

O(c) Convert a `LazyByteString` into a list of `StrictByteString`

foldrChunks :: (StrictByteString -> a -> a) -> a -> ByteString -> a #

Consume the chunks of a lazy ByteString with a natural right fold.

foldlChunks :: (a -> StrictByteString -> a) -> a -> ByteString -> a #

Consume the chunks of a lazy ByteString with a strict, tail-recursive, accumulating left fold.

# Basic interface

cons :: Word8 -> ByteString -> ByteString infixr 5 #

O(1) `cons` is analogous to `(:)` for lists.

cons' :: Word8 -> ByteString -> ByteString infixr 5 #

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 -> Word8 -> ByteString infixl 5 #

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

append :: ByteString -> ByteString -> ByteString #

O(n/c) Append two ByteStrings

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

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

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

O(n/c) Extract the `init` and `last` of a ByteString, returning `Nothing` if it is empty.

- It is no faster than using `init` and `last`

null :: ByteString -> Bool #

O(1) Test whether a ByteString is empty.

length :: ByteString -> Int64 #

O(c) `length` returns the length of a ByteString as an `Int64`

# Transforming ByteStrings

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

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

reverse :: ByteString -> ByteString #

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

intersperse :: Word8 -> ByteString -> ByteString #

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.

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

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.

transpose :: [ByteString] -> [ByteString] #

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

# Reducing `ByteString`s (folds)

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

`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'` 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.

## Special folds

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

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.

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.

# Building ByteStrings

## Scans

scanl #

Arguments

:: (Word8 -> Word8 -> Word8) | accumulator -> element -> new accumulator
-> Word8 | starting value of accumulator
-> ByteString | input of length n
-> ByteString | output of length n+1

`scanl` is similar to `foldl`, but returns a list of successive reduced values from the left.

    scanl f z [x1, x2, ...] == [z, z `f` x1, (z `f` x1) `f` x2, ...]

Note that

    head (scanl f z xs) == z
    last (scanl f z xs) == foldl f z xs

## Accumulating maps

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 ByteString.

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.

## Infinite ByteStrings

repeat :: Word8 -> ByteString #

``repeat` x` is an infinite ByteString, with `x` the value of every element.

replicate :: Int64 -> Word8 -> ByteString #

O(n) ``replicate` n x` is a ByteString of length `n` with `x` the value of every element.

cycle :: HasCallStack => ByteString -> ByteString #

`cycle` ties a finite ByteString into a circular one, or equivalently, the infinite repetition of the original ByteString.

iterate :: (Word8 -> Word8) -> Word8 -> ByteString #

``iterate` f x` returns an infinite ByteString of repeated applications of `f` to `x`:

    iterate f x == [x, f x, f (f x), ...]

## Unfolding ByteStrings

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

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 #

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`.

drop :: Int64 -> ByteString -> ByteString #

O(n/c) `drop` `n xs` returns the suffix of `xs` after the first `n` elements, or `empty` if `n > `length` xs`.

splitAt :: Int64 -> ByteString -> (ByteString, ByteString) #

O(n/c) `splitAt` `n xs` is equivalent to `(`take` n xs, `drop` n xs)`.

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

Similar to `takeWhile`, returns the longest (possibly empty) prefix of elements satisfying the predicate.

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

Similar to `dropWhile`, drops the longest (possibly empty) prefix of elements satisfying the predicate and returns the remainder.

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

Similar to `span`, returns the longest (possibly empty) prefix of elements satisfying the predicate and the remainder of the string.

`span` `p` is equivalent to ``break` (not . p)` and to `(`takeWhile` p &&& `dropWhile` p)`.

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

Similar to `break`, returns the longest (possibly empty) prefix of elements which do not satisfy the predicate and the remainder of the string.

`break` `p` is equivalent to ``span` (not . p)` and to `(`takeWhile` (not . p) &&& `dropWhile` (not . p))`.

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

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

inits :: ByteString -> [ByteString] #

Returns all initial segments of the given `ByteString`, shortest first.

tails :: ByteString -> [ByteString] #

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

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`.

## Breaking into many substrings

split :: Word8 -> ByteString -> [ByteString] #

O(n) Break a `ByteString` into pieces separated by the byte argument, consuming the delimiter. I.e.

    split 10  "a\nb\nd\ne" == ["a","b","d","e"]   -- fromEnum '\n' == 10
    split 97  "aXaXaXa"    == ["","X","X","X",""] -- fromEnum 'a' == 97
    split 120 "x"          == ["",""]             -- fromEnum 'x' == 120
    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 `ByteString`s that are slices of the original.

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 (==97) "aabbaca" == ["","","bb","c",""] -- fromEnum 'a' == 97
    splitWith undefined ""     == []                  -- and not [""]

# Predicates

isPrefixOf :: ByteString -> ByteString -> Bool #

O(n) The `isPrefixOf` function takes two ByteStrings and returns `True` iff 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

# Search ByteStrings

## Searching by equality

elem :: Word8 -> ByteString -> Bool #

O(n) `elem` is the `ByteString` membership predicate.

notElem :: Word8 -> ByteString -> Bool #

O(n) `notElem` is the inverse of `elem`

## Searching with a 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

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.

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)

# Indexing ByteStrings

index :: HasCallStack => ByteString -> Int64 -> Word8 #

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

This is a partial function, consider using `indexMaybe` instead.

elemIndex :: Word8 -> ByteString -> Maybe Int64 #

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 Int64 #

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-0.10.6.0

elemIndices :: Word8 -> ByteString -> [Int64] #

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).

findIndex :: (Word8 -> Bool) -> ByteString -> Maybe Int64 #

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 -> [Int64] #

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

count :: Word8 -> ByteString -> Int64 #

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.

# Zipping and unzipping ByteStrings

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.

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.

# Low level conversions

## Copying ByteStrings

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.

# I/O with `ByteString`s

## Standard input and output

getContents :: MonadIO m => m LByteString #

Lifted `getContents`

putStr :: MonadIO m => LByteString -> m () #

Lifted `putStr`

putStrLn :: MonadIO m => LByteString -> m () #

Lifted `putStrLn`

interact :: MonadIO m => (LByteString -> LByteString) -> m () #

Lifted `interact`

## Files

readFile :: MonadIO m => FilePath -> m LByteString #

Lifted `readFile`

writeFile :: MonadIO m => FilePath -> LByteString -> m () #

Lifted `writeFile`

appendFile :: MonadIO m => FilePath -> LByteString -> m () #

Lifted `appendFile`

## I/O with Handles

hGetContents :: MonadIO m => Handle -> m LByteString #

Lifted `hGetContents`

hGet :: MonadIO m => Handle -> Int -> m LByteString #

Lifted `hGet`

hGetNonBlocking :: MonadIO m => Handle -> Int -> m LByteString #

Lifted `hGetNonBlocking`

hPut :: MonadIO m => Handle -> LByteString -> m () #

Lifted `hPut`

hPutNonBlocking :: MonadIO m => Handle -> LByteString -> m LByteString #

Lifted `hPutNonBlocking`

hPutStr :: MonadIO m => Handle -> LByteString -> m () #

Lifted `hPutStr`