From de5ee043826bce23906bfcb351a2702e1aa88270 Mon Sep 17 00:00:00 2001
From: Dustin Mierau <dustin@mierau.me>
Date: Mon, 27 Nov 2023 12:39:11 -0800
Subject: Getting started

---
 Hotline/Utility/DataExtensions.swift | 54 ++++++++++++++++++++++++++++++++++++
 1 file changed, 54 insertions(+)
 create mode 100644 Hotline/Utility/DataExtensions.swift

(limited to 'Hotline/Utility')

diff --git a/Hotline/Utility/DataExtensions.swift b/Hotline/Utility/DataExtensions.swift
new file mode 100644
index 0000000..9530416
--- /dev/null
+++ b/Hotline/Utility/DataExtensions.swift
@@ -0,0 +1,54 @@
+import Foundation
+
+enum Endianness {
+  case big
+  case little
+}
+
+extension Data {
+  func readUInt8(at offset: Int) -> UInt8? {
+    guard offset >= 0, offset + MemoryLayout<UInt8>.size <= self.count else {
+      return nil
+    }
+    return self[offset]
+  }
+  
+  func readUInt16(at offset: Int, endianness: Endianness = .big) -> UInt16? {
+    guard offset >= 0, offset + MemoryLayout<UInt16>.size <= self.count else {
+      return nil
+    }
+    let value = self.subdata(in: offset..<(offset + MemoryLayout<UInt16>.size)).withUnsafeBytes { $0.load(as: UInt16.self) }
+    return (endianness == .big) ? value.bigEndian : value.littleEndian
+  }
+  
+  func readUInt32(at offset: Int, endianness: Endianness = .big) -> UInt32? {
+    guard offset >= 0, offset + MemoryLayout<UInt32>.size <= self.count else {
+      return nil
+    }
+    let value = self.subdata(in: offset..<(offset + MemoryLayout<UInt32>.size)).withUnsafeBytes { $0.load(as: UInt32.self) }
+    return (endianness == .big) ? value.bigEndian : value.littleEndian
+  }
+  
+  func read<T: FixedWidthInteger>(type: T.Type, at offset: Int) -> T? {
+    guard offset >= 0, offset + MemoryLayout<T>.size <= self.count else {
+      return nil // Ensure the offset is within the Data's range
+    }
+    
+    return self.withUnsafeBytes { rawBufferPointer in
+      let pointer = rawBufferPointer.baseAddress!
+        .advanced(by: offset)
+        .assumingMemoryBound(to: T.self)
+      
+//      switch endianness {
+//      case .big:
+      return pointer.pointee.bigEndian
+//      case .little:
+//        return pointer.pointee.littleEndian
+//      }
+    }
+  }
+  
+  func readString(at offset: Int, length: Int, encoding: String.Encoding) -> String? {
+    return String(data: self[offset..<(offset + length)], encoding: encoding)
+  }
+}
-- 
cgit