Reading Data into a Struct in Swift

Question

I\'m trying to read bare Data into a Swift 4 struct using the withUnsafeBytes method. The problem

The network UDP packet has t

Answer 1

Since Swift 3 Data conforms to RandomAccessCollection, MutableCollection, RangeReplaceableCollection. So you can simply create a custom initializer to initialise your struct properties as follow:

struct XPLBeacon {
    let majorVersion, minorVersion: UInt8             // 1 + 1 = 2 Bytes
    let applicationHostId, versionNumber: UInt32      // 4 + 4 = 8 Bytes
    init(data: Data) {
        self.majorVersion = data[0]
        self.minorVersion = data[1]
        self.applicationHostId = data
            .subdata(in: 2..<6)
            .withUnsafeBytes { $0.load(as: UInt32.self) }
        self.versionNumber = data
            .subdata(in: 6..<10)
            .withUnsafeBytes { $0.load(as: UInt32.self) }
    }
}

---

var data = Data([0x01,0x02, 0x0A, 0x00, 0x00, 0x00, 0x0B, 0x00, 0x00,0x00])
print(data as NSData)     // "{length = 10, bytes = 0x01020a0000000b000000}\n" <01020a00 00000b00 0000>

let beacon = XPLBeacon(data: data)
beacon.majorVersion       // 1
beacon.minorVersion       // 2
beacon.applicationHostId  // 10
beacon.versionNumber      // 11