Swift version: 5.6
Apple gives us dedicated API for compressing binary data, although annoyingly it exists on NSData
without being bridged neatly to Swift’s native Data
type. Fortunately, that conversion is trivial, so this functionality isn’t hard to use.
Here’s how to use it:
do {
let compressedData = try (yourData as NSData).compressed(using: .lzfse)
// use your compressed data
} catch {
print(error.localizedDescription)
}
Although it’s common for folks to call compression and decompression zipping and unzipping, zip is one particular file format and the code above uses the LZFSE compression algorithm instead. This an Apple-design compression algorithm that is recommended unless you specifically need one of the others. The alternatives are:
.lz4
compresses less effectively, but is significantly faster..zlib
is the recommended general purpose algorithm to use if you want cross compatibility with non-Apple devices..lzma
compresses the most effectively, but should only be used if memory usage and speed are not important. Apple specifically states that this might use a large amount of memory, and so it should be avoided if you’re trying to compress large amounts of data. This is about 10x slower than the alternatives.If you want to decompress some data, you should use the counterpart method, decompressed(using:)
, which works in the same way.
BUILD THE ULTIMATE PORTFOLIO APP Most Swift tutorials help you solve one specific problem, but in my Ultimate Portfolio App series I show you how to get all the best practices into a single app: architecture, testing, performance, accessibility, localization, project organization, and so much more, all while building a SwiftUI app that works on iOS, macOS and watchOS.
Sponsor Hacking with Swift and reach the world's largest Swift community!
Available from iOS 13.0
This is part of the Swift Knowledge Base, a free, searchable collection of solutions for common iOS questions.
Link copied to your pasteboard.