map -package:containers -package:hedgehog -package:incipit-base -package:ghc package:bytestring

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

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

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

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.

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.

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.

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.

Map a function over a ByteString and concatenate the results

Create a Builder that encodes each Word8 of a strict ByteString using a BoundedPrim. For example, we can write a Builder that filters a strict ByteString as follows.

import qualified Data.ByteString.Builder.Prim as P

filterBS p = P.condB p (P.liftFixedToBounded P.word8) P.emptyB

Heavy inlining. Encode all bytes of a strict ByteString from left-to-right with a FixedPrim. This function is quite versatile. For example, we can use it to construct a Builder that maps every byte before copying it to the buffer to be filled.

mapToBuilder :: (Word8 -> Word8) -> S.ByteString -> Builder
mapToBuilder f = primMapByteStringFixed (contramapF f word8)

We can also use it to hex-encode a strict ByteString as shown by the byteStringHex example above.

Chunk-wise application of primMapByteStringBounded.

Heavy inlining. Encode all bytes of a lazy ByteString from left-to-right with a FixedPrim.

Create a Builder that encodes a list of values consecutively using a BoundedPrim for each element. This function is more efficient than

mconcat . map (primBounded w)

or

foldMap (primBounded w)

because it moves several variables out of the inner loop.

Encode a list of values from left-to-right with a FixedPrim.

Change a BoundedPrim such that it first applies a function to the value to be encoded. Note that BoundedPrims are Contravariant http://hackage.haskell.org/package/contravariant. Hence, the following laws hold.

contramapB id = id
contramapB f . contramapB g = contramapB (g . f)

Change a primitives such that it first applies a function to the value to be encoded. Note that primitives are Contravariant http://hackage.haskell.org/package/contravariant. Hence, the following laws hold.

contramapF id = id
contramapF f . contramapF g = contramapF (g . f)

Map a function over a ByteString and concatenate the results