Swift Library - Pencil

Read/Write struct data on device more easily.

Transcript

1. Pencil Swift Library Naruki Chigira - Timers inc. GitHub: naru-jpn, Twitter: @naruchigi https://github.com/naru-jpn/pencil
2. Motivation / Concept
3. Protocol Buffers (Apple) https://github.com/apple/swift-protobuf
4. Protocol buffers are a language-neutral, platform-neutral extensible mechanism for serializing structured data. Protocol Buffers (Google) https://developers.google.com/protocol-buffers/
5. Protocol Buffers is a method of serializing structured data. It is useful in developing programs to communicate with each other over a wire or for storing data. … The design goals for Protocol Buffers emphasized simplicity and performance. In particular, it was designed to be smaller and faster than XML. Protocol Buffers (Wikipedia) https://en.wikipedia.org/wiki/Protocol_Buffers
6. Value types + Serialize + Storing data on device Pencil
7. ✏… Read/Write struct data on device more easily. Pencil
8. Sample Code
9. Write Standard Values (Int) // get file URL guard let storedURL = Directory.Documents?.append(path: "num.data") else { return } let num: Int = 2016 // write to file num.write(to: storedURL)
10. Read Standard Values (Int) // read from file path let num = Int.value(from: storedURL)
11. Write Standard Values ([Int]) // get file URL guard let storedURL = Directory.Documents?.append(path: "nums.data") else { return } let nums: Int = [2016, 11, 29] // write to file nums.write(to: storedURL)
12. Read Standard Values ([Int]) // read from file path let nums = [Int].value(from: storedURL)
13. Standard Values Int UInt Float Double String Array Dictionary Int8, Int16, Int32, Int64 UInt8, UInt16, UInt32, UInt64
14. Custom Struct // Custom Struct struct Sample: CustomReadWriteElement { // Parameters let dictionary: [String: Int] let array: [Int]? let identifier: String // Function returns Sample from Components static var read: (Components) -> Sample? = { components in return Sample.init =<> components.component(for: "dictionary", defaultValue: ["a": 100]) -<> components.component(for: "array") -<> components.component(for: "identifier", defaultValue: "abc123") } }
15. Write Custom Struct // get file URL guard let storedURL = Directory.Documents?.append(path: "sample.data") else { return } let sample: Sample = Sample(dictionary: ["a": 2, "b": 5], array: [2, 3], identifier: “id") // write to file sample.write(to: storedURL)
16. Read Custom Struct // read from file path let sample = Sample.value(from: storedURL)
17. Write Custom Struct ([Sample]) // get file URL guard let storedURL = Directory.Documents?.append(path: "samples.data") else { return } let sample: Sample = Sample(dictionary: ["a": 2, "b": 5], array: [2, 3], identifier: “id”) let samples: [Samples] = [sample, sample, sample] // write to file samples.write(to: storedURL)
18. Read Custom Struct ([Sample]) // read from file path let samples = [Sample].value(from: storedURL)
19. Example
20. https://arxiv.org
21. Entry struct Entry: Equatable, CustomDebugStringConvertible, CustomReadWriteElement { var id: String = "" var updated: Double = NSDate(timeIntervalSince1970: 0.0).timeIntervalSince1970 var published: Double = NSDate(timeIntervalSince1970: 0.0).timeIntervalSince1970 var title: String = "" var summary: String = "" var authors: [Entry.Author] = [] var updatedDay: String = "" var publishedDay: String = "" var htmlLink: String = "" var pdfLink: String = "" var primaryCategory: String = "" struct Author: CustomDebugStringConvertible, CustomReadWriteElement { // … } // … }
22. Entry.Author struct Author: CustomDebugStringConvertible, CustomReadWriteElement { var name: String = "" var affiliation: String = "" static var read: (Components) -> Entry.Author? = { components in return Entry.Author( name: components.component(for: "name", defaultValue: ""), affiliation: components.component(for: "affiliation", defaultValue: "") ) } // … }
23. Implementation
24. Data Structure Format identifier header body
25. Format identifier header body length + type_name (UInt8) Data Structure
26. Data Structure (Int) identifier header body length 6 → <03496e74 06000000 00000000> <03> <496e74> + type_name <> <06000000 00000000>
27. Data Structure (String) identifier header body length "pencil" → <06537472 696e6706 0070656e 63696c> <06> <53747269 6e67> + type_name <0600> <70656e63 696c>
28. Data Structure ([Int]) identifier header body length [1,2,3] → <0a417272 61793c49 6e743e03 000c0000 000c0000 000c0000 0003496e 74010000 00000000 0003496e 74020000 00000000 0003496e 74030000 00000000 00> <0a> <417272 61793c49 6e743e> + type_name <03000c00 00000c00 00000c00 0000> <03496e74 01000000 00000000 03496e74 02000000 00000000 03496e74 03000000 00000000>
29. Data Structure ([Int]) identifier header body length [1,2,3] → <0a417272 61793c49 6e743e03 000c0000 000c0000 000c0000 0003496e 74010000 00000000 0003496e 74020000 00000000 0003496e 74030000 00000000 00> <0a> <417272 61793c49 6e743e> + type_name <03000c00 00000c00 00000c00 0000> <03496e74 01000000 00000000 03496e74 02000000 00000000 03496e74 03000000 00000000>
30. Data Structure ([Int]) identifier header body length [1,2,3] → <0a417272 61793c49 6e743e03 000c0000 000c0000 000c0000 0003496e 74010000 00000000 0003496e 74020000 00000000 0003496e 74030000 00000000 00> <0a> <417272 61793c49 6e743e> + type_name <03000c00 00000c00 00000c00 0000> <03496e74 01000000 00000000 03496e74 02000000 00000000 03496e74 03000000 00000000>
31. and more.
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