Upgrade to Pro
— share decks privately, control downloads, hide ads and more …
Speaker Deck
Features
Speaker Deck
PRO
Sign in
Sign up for free
Search
Search
Working With Binary Data in Swift
Search
JP Simard
October 29, 2015
Programming
4
1.2k
Working With Binary Data in Swift
Presented at Swift Summit SF 2015.
Source available here:
https://github.com/jpsim/talks
JP Simard
October 29, 2015
Tweet
Share
More Decks by JP Simard
See All by JP Simard
Unconventional Swift Patterns
jpsim
0
3.4k
Pushing Envoy Beyond the Edge
jpsim
0
39
Lessons from Mobile Networking at Scale
jpsim
0
55
Bespoke, Artisanal Swift Static Analysis
jpsim
2
1.7k
Performance Profiling Swift on Linux
jpsim
4
1.5k
Realm Mobile Platform Experience
jpsim
3
120
"Watch Your Language!": The road to clean code with SwiftLint
jpsim
6
78k
Mastering Realm Notifications
jpsim
1
34k
Realm 1.0 Party
jpsim
1
100
Other Decks in Programming
See All in Programming
実践!App Intents対応
yuukiw00w
1
350
AI時代のドメイン駆動設計-DDD実践におけるAI活用のあり方 / ddd-in-ai-era
minodriven
23
9k
フロントエンドのmonorepo化と責務分離のリアーキテクト
kajitack
2
140
State of CSS 2025
benjaminkott
1
120
KessokuでDIでもgoroutineを活用する / Go Connect #6
mazrean
0
110
CEDEC2025 長期運営ゲームをあと10年続けるための0から始める自動テスト ~4000項目を50%自動化し、月1→毎日実行にした3年間~
akatsukigames_tech
0
150
ライブ配信サービスの インフラのジレンマ -マルチクラウドに至ったワケ-
mirrativ
2
260
LLMOpsのパフォーマンスを支える技術と現場で実践した改善
po3rin
8
980
学習を成果に繋げるための個人開発の考え方 〜 「学習のための個人開発」のすすめ / personal project for leaning
panda_program
1
110
Flutter로 Gemini와 MCP를 활용한 Agentic App 만들기 - 박제창 2025 I/O Extended Seoul
itsmedreamwalker
0
150
『リコリス・リコイル』に学ぶ!! 〜キャリア戦略における計画的偶発性理論と変わる勇気の重要性〜
wanko_it
1
590
Terraform やるなら公式スタイルガイドを読もう 〜重要項目 10選〜
hiyanger
13
3.2k
Featured
See All Featured
ピンチをチャンスに:未来をつくるプロダクトロードマップ #pmconf2020
aki_iinuma
126
53k
For a Future-Friendly Web
brad_frost
179
9.9k
Product Roadmaps are Hard
iamctodd
PRO
54
11k
How STYLIGHT went responsive
nonsquared
100
5.7k
4 Signs Your Business is Dying
shpigford
184
22k
Helping Users Find Their Own Way: Creating Modern Search Experiences
danielanewman
29
2.8k
RailsConf 2023
tenderlove
30
1.2k
Build The Right Thing And Hit Your Dates
maggiecrowley
37
2.8k
Designing for humans not robots
tammielis
253
25k
Performance Is Good for Brains [We Love Speed 2024]
tammyeverts
10
1k
Refactoring Trust on Your Teams (GOTO; Chicago 2020)
rmw
34
3.1k
Building Adaptive Systems
keathley
43
2.7k
Transcript
Working with Binary Data in Swift
JP Simard @ Realm
None
Options → NSData → [UInt8] → withUnsafePointer() → ???
Layout-Aligned Structs
func encode<T>(var value: T) -> NSData { return withUnsafePointer(&value) {
p in NSData(bytes: p, length: sizeofValue(value)) } } func decode<T>(data: NSData) -> T { let pointer = UnsafeMutablePointer<T>.alloc(sizeof(T)) data.getBytes(pointer, length: sizeof(T)) return pointer.move() }
enum Either<T> { case Left(T) case Right(T) } let value
= Either.Left("Swift Summit") let data = encode(value) data // => <NSData> let decoded: Either<String> = decode(data) decoded // => Either.Left("Swift Summit")
None
None
Get SourceKit syntax map struct A { subscript(index: Int) ->
() { return () } }
Result 00 00 00 00 00 00 00 00 30
00 00 00 00 00 00 00 40 4c 81 01 01 00 00 00 00 00 00 00 0c 00 00 00 78 4c 81 01 01 00 00 00 07 00 00 00 14 00 00 00 b0 4c 81 01 01 00 00 00 12 00 00 00 1e 00 00 00 00
Result 00 00 00 00 00 00 00 00 30
00 00 00 00 00 00 00 --------16 bytes------- --------16 bytes------- 40 4c 81 01 01 00 00 00 00 00 00 00 0c 00 00 00 --------16 bytes------- --------16 bytes------- 78 4c 81 01 01 00 00 00 07 00 00 00 14 00 00 00 --------16 bytes------- --------16 bytes------- b0 4c 81 01 01 00 00 00 12 00 00 00 1e 00 00 00 --------16 bytes------- --------16 bytes------- 00
!
struct SyntaxToken { let type: String let offset: Int let
length: Int }
Strideable
tokens = 16.stride(through: numberOfTokens * 16, by: 16).map { parserOffset
in . }
tokens = 16.stride(through: numberOfTokens * 16, by: 16).map { parserOffset
in var uid = UInt64(0), offset = 0, length = 0 data.getBytes(&uid, range: NSRange(location: parserOffset, length: 8)) data.getBytes(&offset, range: NSRange(location: 8 + parserOffset, length: 4)) data.getBytes(&length, range: NSRange(location: 12 + parserOffset, length: 4)) }
tokens = 16.stride(through: numberOfTokens * 16, by: 16).map { parserOffset
in var uid = UInt64(0), offset = 0, length = 0 data.getBytes(&uid, range: NSRange(location: parserOffset, length: 8)) data.getBytes(&offset, range: NSRange(location: 8 + parserOffset, length: 4)) data.getBytes(&length, range: NSRange(location: 12 + parserOffset, length: 4)) return SyntaxToken( type: stringForSourceKitUID(uid) ?? "unknown", offset: offset, length: length >> 1 ) }
Collection of Bytes → Making our own → Conforming to
ExtensibleCollectionType → What Index type should we use? Int?
Just end up with [UInt8]
Links → SourceKittenFramework SyntaxMap → Convert structs and enums to
NSData → robnapier.net/nsdata → Simon Lewis on parsing OLE/COM → github.com/realm/jazzy → realm.io
try! ask(...) struct Question { let value: String let canJPAnswer:
Bool } func ask<S: SequenceType where S.Generator.Element == Question>(questions: S) throws { // excercise for attendees }