Note: This package is obsolete and should no longer be used. This repository stays up purely for archival purposes.
The data encodings library strives to provide implementations in Haskell of every major data encoding, and a few minor ones as well. Currently the following encodings are implemented:
- Base16 (
Codec.Binary.Base16
) - Base32 (
Codec.Binary.Base32
) - Base32Hex (
Codec.Binary.Base32Hex
) - Base64 (
Codec.Binary.Base64
) - Base64Url (
Codec.Binary.Base64Url
) - Base85 (
Codec.Binary.Base85
) - Python string escaping (
Codec.Binary.PythonString
) - Quoted-Printable (
Codec.Binary.QuotedPrintable
) - URL encoding (
Codec.Binary.Url
) - Uuencode (
Codec.Binary.Uu
) - Xxencode (
Codec.Binary.Xx
) - yEncode (
Codec.Binary.Yenc
)
In some cases the encodings also specify headers and footers for the encoded data. Implementation of that is left for the user of the library.
The module Codec.Binary.DataEncoding provides a type that collects the functions for an individual encoding:
data DataCodec = DataCodec {
encode :: [Word8] -> String,
decode :: String -> Maybe [Word8],
decode' :: String -> [Maybe Word8],
chop :: Int -> String -> [String],
unchop :: [String] -> String
}
It also exposes instances of this type for each encoding:
base16 :: DataCodec
base32 :: DataCodec
base32Hex :: DataCodec
base64 :: DataCodec
base64Url :: DataCodec
uu :: DataCodec
NB There is no instance for yEncoding since the functions in that module have slightly different type signatures.
Each individual encoding module is also exposed and offers four functions:
encode :: [Word8] -> String
decode :: String -> Maybe [Word8]
decode' :: String -> [Maybe Word8]
chop :: Int -> String -> [String]
unchop :: [String] -> String
Implemented as it's defined in RFC 4648.
Each four bit nibble of an octet is encoded as a character in the set 0-9,A-F.
Implemented as it's defined in RFC 4648.
Five octets are expanded into eight so that only the five least significant bits are used. Each is then encoded into a 32-character encoding alphabet.
Implemented as it's defined in RFC 4648.
Just like Base32 but with a different encoding alphabet. Unlike Base64 and Base32, data encoded with Base32Hex maintains its sort order when the encoded data is compared bit wise.
Implemented as it's defined in RFC 4648.
Three octets are expanded into four so that only the six least significant bits are used. Each is then encoded into a 64-character encoding alphabet.
Implemented as it's defined in RFC 4648.
Just like Base64 but with a different encoding alphabet. The encoding alphabet is made URL and filename safe by substituting + and / for - and _ respectively.
Implementation as described in the Wikipedia article.
Implementation of Python's string escaping.
Implemented as defined in RFC 2045.
Implemented as defined in RFC 3986.
Unfortunately uuencode is badly specified and there are in fact several differing implementations of it. This implementation attempts to encode data in the same way as the uuencode
utility found in GNU's sharutils. The workings of chop
and unchop
also follow how sharutils split and unsplit encoded lines.
Implemented as described in the Wikipedia article.
Implemented as it's defined in the 1.3 draft.
The current release is available from [http://hackage.haskell.org/package/dataenc].
The package omnicodec contains two command line tools for encoding and decoding data.
The source is hosted on github and can be downloaded using git:
git clone https://github.com/scrive/dataenc.git