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https://github.com/michaeldorner/bytebackpacker
ByteBackpacker is a small utility written in Swift to pack value types into a Byte array and unpack them back.
https://github.com/michaeldorner/bytebackpacker
bytearray swift swift-3
Last synced: about 2 months ago
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ByteBackpacker is a small utility written in Swift to pack value types into a Byte array and unpack them back.
- Host: GitHub
- URL: https://github.com/michaeldorner/bytebackpacker
- Owner: michaeldorner
- License: mit
- Created: 2016-01-08T20:08:59.000Z (almost 9 years ago)
- Default Branch: master
- Last Pushed: 2021-12-28T18:02:07.000Z (about 3 years ago)
- Last Synced: 2024-10-14T22:21:34.892Z (3 months ago)
- Topics: bytearray, swift, swift-3
- Language: Swift
- Homepage:
- Size: 191 KB
- Stars: 33
- Watchers: 3
- Forks: 10
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
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# ByteBackpacker
> ByteBackpacker is a small utility written in pure Swift to pack value types into a `Byte`¹ array and unpack them back.
Additionally, there is a [`Data`](https://developer.apple.com/reference/foundation/data) (formerly `NSData`) [extension](https://developer.apple.com/library/ios/documentation/Swift/Conceptual/Swift_Programming_Language/Extensions.html) to convert `Data` objects into a `Byte` array.
¹ `Byte` is a [`typealias`](https://developer.apple.com/library/ios/documentation/Swift/Conceptual/Swift_Programming_Language/Declarations.html#//apple_ref/doc/uid/TP40014097-CH34-ID361) for `UInt8`.
## Table of Contents
- [Installation](#installation)
- [Usage](#usage)
- [API](#api)
- [Discussion](#discussion)
- [Contributions](#contributions)
- [Versions](#versions)
- [License](#license)
## Installation
You have three options:
1. Use [Swift Package Manager](https://swift.org/getting-started/#using-the-package-manager):
import PackageDescription
let package = Package(
name: "TestImport",
dependencies: [
.Package(url: "https://github.com/michaeldorner/ByteBackpacker.git")
]
)
2. Use [Cocoapods](https://cocoapods.org): `pod 'ByteBackpacker'`
3. Copy the [`ByteBackpacker.swift`](https://github.com/michaeldorner/ByteBackpacker/blob/master/Sources/ByteBackpacker/ByteBackpacker.swift) file (containing the `ByteBackpacker` class) to your project (not considered as good practice).
Although it can be used in the same way in Objective-C, I had clearly Swift projects in mind. The easiest way for Objective-C users is to embed the `ByteBackpacker.framework`. Of course, Swift users can also do this, but actually I do not see any advantages.
## Usage
Important for a proper usage: **ByteBackpacker does only support value types (e.g. numbers, structs, ...), but no reference types (e.g. classes)!** For further information see [Discussion](#discussion).
All examples can be seen running in the [`ByteBackpackerPlayground.playground`](ByteBackpackerPlayground.playground). Let's have a look on some general use cases:
#### From `Double` to `[Byte]`
```
let aDouble: Double = 1.0
let aByteArray: [Byte] = ByteBackpacker.pack(aDouble)
```
#### From `[Byte]` to `Double`
```
let option_1: Double = ByteBackpacker.unpack(aByteArray)
let option_2 = ByteBackpacker.unpack(aByteArray) as Double
let option_3 = ByteBackpacker.unpack(aByteArray, toType: Double.self)
```
#### From `Double` to `Data` to `[Byte]` to `Double`
```
var anotherDouble: Double = 2.0
let data = Data(bytes: &anotherDouble, count: MemoryLayout.size)
var byteArrayFromNSData = data.toByteArray()
let doubleFromByteArray = ByteBackpacker.unpack(byteArrayFromNSData, toType: Double.self)
```
#### From `[Byte]` to `Data`
```
let anotherByteArray: [Byte] = [0, 0, 0, 0, 0, 0, 8, 64]
let dataFromByteArray = Data(bytes: anotherByteArray)
```
## API
`Byte` is a [`typealias`](https://developer.apple.com/library/ios/documentation/Swift/Conceptual/Swift_Programming_Language/Declarations.html#//apple_ref/doc/uid/TP40014097-CH34-ID361) for `UInt8`.
`ByteOrder` is an `enum` for [Little Endian and Big Endian](https://en.wikipedia.org/wiki/Endianness). Furthermore, there is the option for asking the platform you are using for the native byte order of the system: `ByteOrder.nativeByteOrder`. By default `.nativeByteOrder` is applied for packing and unpacking.
For packing value types into a `[Byte]`, use
```open class func pack( _ value: T, byteOrder: ByteOrder = .nativeByteOrder) -> [Byte]```
For unpacking a `[Byte]` into a value type, use either
```open class func unpack(_ valueByteArray: [Byte], byteOrder: ByteOrder = .nativeByteOrder) -> T```
or otherwise, if you want to use type inference
```open class func unpack(_ valueByteArray: [Byte], toType type: T.Type, byteOrder: ByteOrder = .nativeByteOrder) -> T```
## Discussion
### Generics
There is no way for specifying value types in Swift's generics (see [here the discussion on stackoverflow](http://stackoverflow.com/q/28782532/1864294)). It would be awesome to specify our methods like `func (un)pack(...)` to let the compiler check for value types. So far ByteBackpacker ensures the value type with `assert(...)`.
An open question is how to test the `assert(...)` for this value type check.
I would love to improve this project. Tell me your ideas, here in github, via mail or in [codereview.stackexchange.com](http://codereview.stackexchange.com/questions/114730/type-to-byte-array-conversion-in-swift).
## Contributions
### To-Do
- [x] Find a solution for making sure, that `T` is a value type, but not a reference type
- [x] Add documentation to the source code for a nice Xcode integration
- [ ] Find a solution for testing `assert()`
### Acknowledgements
Many thanks to
* [Martin R](http://codereview.stackexchange.com/users/35991/martin-r) for [his suggestions in codereview.stackexchange.com](http://codereview.stackexchange.com/a/114738/61640)
* [iCodist](https://github.com/iCodist/ByteBackpacker) for his update to Swift 3 and Xcode 8
* [vaggos666](https://github.com/michaeldorner/ByteBackpacker/issues/4) for his remarks to Swift 4
## Versions
(Un)fortunately there is a lot of work going on Swift. This made larger changes to ByteBackpacker needed. The following table shows the compatibility.
| Swift version | 2.0 | 3.0 | 4.0 and later
| :-: | :-: | :-: | :-: |
| ByteBackpacker 1.0 | ✓ | ✗ | ✗
| ByteBackpacker 1.1 | ✗ | ✓ | ✗
| ByteBackpacker 1.2 and later | ✗ | ✓ | ✓
Hopefully the APIs will be stable now.
## License
ByteBackpacker is released under the MIT license. See [LICENSE](LICENSE) for more details.