Data.ByteString.Encoding

data Encoding

Constructors

• UTF8
• UTF16LE
• Latin1
• Hex
• Base64

Instances

• Eq Encoding
• Ord Encoding
• Show Encoding

fromString :: Encoding -> String -> Maybe ByteString

Encode a string to bytes under the given encoding, failing on unrepresentable inputs. Use fromStringLossy for a lenient decoder that doesn't fail. Per encoding, the input is rejected when:

• UTF8: it contains an unpaired surrogate
• UTF16LE: never fails
• Latin1: a UTF-16 code unit is above 0xFF
• Hex: the length is odd, or a character is not a hex digit
• Base64: anything but a canonically padded RFC 4648 encoding, e.g. a length not a multiple of four, a character outside the standard and URL-safe alphabets, = other than as final padding (at most two), or nonzero unused bits in the final data character.

fromStringLossy :: Encoding -> String -> ByteString

Encode a string to bytes under the given encoding, lossily. Substitutions per encoding:

• UTF8: substitutes U+FFFD for an unpaired surrogate
• UTF16LE: exact
• Latin1: masks each code unit to its low byte
• Hex: stops at the first non-hex character or a trailing lone digit
• Base64: skips any character outside the alphabet (whitespace, =, anything else)

toString :: Encoding -> ByteString -> Maybe String

Decode bytes to a string under the given encoding, returning Nothing when a strict UTF decoder rejects the input (invalid UTF-8, or an odd-length UTF-16 buffer)

toStringLossy :: Encoding -> ByteString -> String

Decode bytes to a string under the given encoding, total in every case. Per encoding:

• UTF8: substitutes U+FFFD for invalid bytes
• UTF16LE: drops a trailing odd byte and decodes the even prefix
• Latin1, Hex, Base64: never fail