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
PHPUnitの限界をPlaywrightで補完するテストアプローチ
yuzneri
0
370
Claude Code と OpenAI o3 で メタデータ情報を作る
laket
0
110
Streamlitで実現できるようになったこと、実現してくれたこと
ayumu_yamaguchi
2
270
商品比較サービス「マイベスト」における パーソナライズレコメンドの第一歩
ucchiii43
0
270
Amazon Q CLI開発で学んだAIコーディングツールの使い方
licux
3
170
リバースエンジニアリング新時代へ! GhidraとClaude DesktopをMCPで繋ぐ/findy202507
tkmru
7
1.7k
0から始めるモジュラーモノリス-クリーンなモノリスを目指して
sushi0120
0
250
大規模FlutterプロジェクトのCI実行時間を約8割削減した話
teamlab
PRO
0
440
DynamoDBは怖くない!〜テーブル設計の勘所とテスト戦略〜
hyamazaki
0
180
Git Sync を超える!OSS で実現する CDK Pull 型デプロイ / Deploying CDK with PipeCD in Pull-style
tkikuc
4
520
What's new in Adaptive Android development
fornewid
0
130
オホーツクでコミュニティを立ち上げた理由―地方出身プログラマの挑戦 / TechRAMEN 2025 Conference
lemonade_37
1
430
Featured
See All Featured
Thoughts on Productivity
jonyablonski
69
4.8k
Build The Right Thing And Hit Your Dates
maggiecrowley
37
2.8k
Design and Strategy: How to Deal with People Who Don’t "Get" Design
morganepeng
130
19k
Statistics for Hackers
jakevdp
799
220k
Measuring & Analyzing Core Web Vitals
bluesmoon
7
540
The Language of Interfaces
destraynor
158
25k
How to train your dragon (web standard)
notwaldorf
96
6.1k
No one is an island. Learnings from fostering a developers community.
thoeni
21
3.4k
Connecting the Dots Between Site Speed, User Experience & Your Business [WebExpo 2025]
tammyeverts
8
420
Chrome DevTools: State of the Union 2024 - Debugging React & Beyond
addyosmani
7
790
How To Stay Up To Date on Web Technology
chriscoyier
790
250k
The Web Performance Landscape in 2024 [PerfNow 2024]
tammyeverts
8
750
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 }