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GHC 9.10.3 · lts/ghc-9.10.x · c74966e · 2026-09-27

Modulebase32-0.4Haskell2010

Data.Text.Lazy.Encoding.Base32

This module contains Text-valued combinators for implementing the RFC 4648 specification of the Base32 encoding format. This includes strictly padded/unpadded decoding variants, as well as internal and external validation for canonicity.

  • 10 values
  • Packagebase32-0.4
  • Exports10
  • LanguageHaskell2010
  • LicenceBSD-3-Clause
  • SourceBase32.hs

Encoding

2 declarations

Encode a Text value in Base32 without padding. Note that for Base32, padding is optional. If you call this function, you will simply be encoding as Base32 and stripping padding chars from the output.

See: RFC-4648 section 6

Examples:
Example1 expression
encodeBase32Unpadded "Sun""KN2W4"

Decoding

6 declarations

Decode an arbitrarily padded Base32-encoded Text value. If its length is not a multiple of 4, then padding chars will be added to fill out the input to a multiple of 4 for safe decoding as base32 encodings are optionally padded.

Note: This function makes sure that decoding is total by deferring to decodeUtf8. This will always round trip for any valid Base32-encoded text value, but it may not round trip for bad inputs. The onus is on the caller to make sure inputs are valid. If unsure, defer to decodeBase32With and pass in a custom decode function.

See: RFC-4648 section 6

Examples:
Example1 expression
decodeBase32 "KN2W4==="Right "Sun"
Example1 expression
decodeBase32 "KN2W4"Right "Sun"
Example1 expression
decodeBase32 "KN2W==="Left "Base32-encoded bytestring has invalid padding"

Decode an unpadded Base32 encoded Text value.

Note: This function makes sure that decoding is total by deferring to decodeUtf8. This will always round trip for any valid Base32-encoded text value, but it may not round trip for bad inputs. The onus is on the caller to make sure inputs are valid. If unsure, defer to decodeBase32WUnpaddedWith and pass in a custom decode function.

See: RFC-4648 section 6

Examples:
Example1 expression
decodeBase32Unpadded "KN2W4"Right "Sun"
Example1 expression
decodeBase32Unpadded "KN2W4==="Left "Base32-encoded bytestring has invalid padding"
valuedecodeBase32UnpaddedWith
  1. :: (ByteString -> Either err Text)

    convert a bytestring to text (e.g. decodeUtf8')

  2. -> ByteString

    Input text to decode

  3. -> Either (Base32Error err) Text
#

Attempt to decode an unpadded lazy ByteString value as Base32, converting from ByteString to Text according to some encoding function. In practice, This is something like decodeUtf8', which may produce an error.

See: RFC-4648 section 6

Examples:
decodeBase32UnpaddedWith decodeUtf8'
  :: ByteString -> Either (Base32Error UnicodeException) Text

Decode an padded Base32 encoded Text value

Note: This function makes sure that decoding is total by deferring to decodeUtf8. This will always round trip for any valid Base32-encoded text value, but it may not round trip for bad inputs. The onus is on the caller to make sure inputs are valid. If unsure, defer to decodeBase32PaddedWith and pass in a custom decode function.

See: RFC-4648 section 6

Examples:
Example1 expression
decodeBase32Padded "KN2W4==="Right "Sun"
Example1 expression
decodeBase32Padded "KN2W4"Left "Base32-encoded bytestring requires padding"
valuedecodeBase32PaddedWith
  1. :: (ByteString -> Either err Text)

    convert a bytestring to text (e.g. decodeUtf8')

  2. -> ByteString

    Input text to decode

  3. -> Either (Base32Error err) Text
#

Attempt to decode a padded lazy ByteString value as Base32, converting from ByteString to Text according to some encoding function. In practice, This is something like decodeUtf8', which may produce an error.

See: RFC-4648 section 6

Example:
decodeBase32PaddedWith decodeUtf8'
  :: ByteString -> Either (Base32Error UnicodeException) Text

Validation

2 declarations
valueisBase32 :: Text -> Bool
#

Tell whether a Text value is Base32-encoded

Examples:
Example1 expression
isBase32 "KN2W4"True
Example1 expression
isBase32 "KN2W4==="True
Example1 expression
isBase32 "KN2W4=="False
valueisValidBase32 :: Text -> Bool
#

Tell whether a Text value is a valid Base32 format.

This will not tell you whether or not this is a correct Base32 representation, only that it conforms to the correct shape. To check whether it is a true Base32 encoded Text value, use isBase32.

Examples:
Example1 expression
isValidBase32 "KN2W4"True
Example1 expression
isValidBase32 "KN2W4="False
Example1 expression
isValidBase32 "KN2W4%"False