base64
Copyright(c) 2019-2026 Emily Pillmore
LicenseBSD-style
MaintainerEmily Pillmore <emilypi@cohomolo.gy>
Stabilitystable
Portabilitynon-portable
Safe HaskellNone
LanguageHaskell2010

Data.ByteString.Short.Base64

Description

This module contains ShortByteString-valued combinators for implementing the RFC 4648 specification of the Base64 encoding format. This includes lenient decoding variants, as well as internal and external validation for canonicity.

Synopsis

Encoding

encodeBase64 :: ShortByteString -> Base64 'StdPadded ShortText Source #

Encode a ShortByteString value as Base64 ShortText with padding.

See: RFC-4648 section 4

Examples:

>>> encodeBase64 "Sun"
"U3Vu"

encodeBase64' :: ShortByteString -> Base64 'StdPadded ShortByteString Source #

Encode a ShortByteString value as a Base64 ShortByteString value with padding.

See: RFC-4648 section 4

Examples:

>>> encodeBase64' "Sun"
"U3Vu"

Decoding

decodeBase64 :: forall (k :: Alphabet). StdAlphabet k => Base64 k ShortByteString -> ShortByteString Source #

Decode a padded Base64-encoded ShortByteString value.

See: RFC-4648 section 4

Examples:

>>> decodeBase64 $ assertBase64 @'StdPadded "U3Vu"
"Sun"

decodeBase64Untyped :: ShortByteString -> Either Text ShortByteString Source #

Decode a padded Base64-encoded ShortByteString value.

See: RFC-4648 section 4

Examples:

>>> decodeBase64Untyped "U3Vu"
Right "Sun"
>>> decodeBase64Untyped "U3V"
Left "Base64-encoded bytestring requires padding"
>>> decodeBase64Untyped "U3V="
Left "non-canonical encoding detected at offset: 2"

decodeBase64Lenient :: ShortByteString -> ShortByteString Source #

Leniently decode an unpadded Base64-encoded ShortByteString value. This function will not generate parse errors. If input data contains padding chars, then the input will be parsed up until the first pad character.

Note: This is not RFC 4648-compliant.

Examples:

>>> decodeBase64Lenient "U3Vu"
"Sun"
>>> decodeBase64Lenient "U3V"
"Su"
>>> decodeBase64Lenient "U3V="
"Su"

Parsing

parseBase64 :: ShortByteString -> Either Text (Base64 'StdPadded ShortByteString) Source #

Parse a canonical, padded Base64-encoded ShortByteString value.

Checks the alphabet, length, padding, and unused padding bits. On success, returns the original encoded value wrapped in Base64, ready for decodeBase64. On failure, returns the same error as decodeBase64Untyped. The input is neither decoded nor normalized in the returned value.

Examples:

>>> parseBase64 "U3Vu"
Right "U3Vu"
>>> fmap decodeBase64 (parseBase64 "U3Vu")
Right "Sun"
>>> parseBase64 "U3V"
Left "Base64-encoded bytestring requires padding"
>>> parseBase64 "U3V="
Left "non-canonical encoding detected at offset: 2"

Since: 2.0