Base85

⛔️ Deprecated

Please use the Bases Package.

Base85 is a Swift library to convert data from Base-85 and vice versa. The API was designed to easily replace the Foundation's built-in Base-64 encoding API.

Installation

You can install this package through Swift Package Manager. Either add this to your Package.swift:

dependencies: [
    .package(url: "https://github.com/pambrozy/Base85", .upToNextMajor(from: "1.0.0")),
    ...
],

Or, by using Xcode:

Select File → Swift Packages → Add Package Dependency...
Enter package URL: https://github.com/pambrozy/Base85

Usage

Foundation

To encode data use the following functions:

let encodedData = data.base85EncodedData()

let encodedString = data.base85EncodedString()

You can also specify encoding options and character set (the default is RFC 1924, see all):

data.base85EncodedData(options: .lineLength64Characters,
                       encoding: .z85)

data.base85EncodedString(options: [.endLineWithCarriageReturn,
                                   .lineLength76Characters],
                         encoding: .adobeAscii85)

In order to decode data:

let fromString = Data(base85Encoded: "JQEepgAAAABM9s8PUbctjl7/Wxk=")

let fromData = Data(base85Encoded: encodedData,
                    options: .ignoreUnknownCharacters,
                    encoding: .rfc1924)

You can also use this library to encode and decode raw data from and into JSON:

let encoder = JSONEncoder()
encoder.dataEncodingStrategy = .base85

let decoder = JSONDecoder()
decoder.dataDecodingStrategy = .base85(encoding: .btoa)

Standalone

To encode data:

// The type of `data` is [UInt8]
let encoded = Base85.encode(data, encoding: .rfc1924)

To decode data:

// The type of `data` is [UInt8]
let decoded = Base85.decode(data, encoding: .rfc1924)

Character sets

This package comes with some character sets build in. They are referred in code as Base85.Encoding. The default encoding is RFC 1924.

Built in character sets:

Encoding	ascii	btoa	Ascii85 (Adobe)	RFC 1924	Z85
Characters	`!` - `u`	`!` - `u`	`!` - `u`	`0` - `~`	`0` - `#`
Beginning of string	-	-	`<~`	-	-
End of string	-	`x`	`~>`	-	-
Four zeros	-	`z`	`z`	-	-
Four spaces	-	`y`	-	-

Custom character set

You can customize each character set by using this static method:

let customizedBtoa = Base85.Encoding.customized(baseEncoding: .btoa,
                                                startDelimeter: nil,
                                                endDelimeter: "x",
                                                representFourZerosAs: "z",
                                                representFourSpacesAs: nil)

You can also create a fully custom character set, by using the following method:

Base85.Encoding.custom(characters: [Character],
                       startDelimeter: String?,
                       endDelimeter: String?,
                       representFourZerosAs zeros: Character?,
                       representFourSpacesAs spaces: Character?)

The smallest character value cannot be smaller than 33 (ASCII "!").
The number of characters should be 85.

Todo

Test Foundation extensions
Test customized and custom encoding
Make Base85.encode and Base85.decode throw an error instead of returning nil in case of failure

License

This package is released under The MIT License. See LICENSE for details.

pambrozy / Base85