Fix max device name chars

NearbyShare/Connection/NearbyConnectionManager.swift

@@ -44,7 +44,6 @@ public class NearbyConnectionManager: NSObject, NetServiceDelegate, InboundNearb
     private static let customDeviceNameKey = "com.leonboettger.quickdrop.deviceName"
     
     public let endpointID: [UInt8] = generateEndpointID()
-    public static let maxNameChars = 31
     
     public static let shared = NearbyConnectionManager()
     
@@ -151,13 +150,13 @@ public class NearbyConnectionManager: NSObject, NetServiceDelegate, InboundNearb
         let deviceType = isMac() ? RemoteDeviceInfo.DeviceType.computer : (isiPadOrMac() ? .tablet : .phone)
         
         if let customName = getCustomDeviceName() {
-            return EndpointInfo(name: String(customName.prefix(Self.maxNameChars)), deviceType: deviceType)
+            return EndpointInfo(name: String(customName), deviceType: deviceType)
         }
         
         #if os(macOS)
-        return EndpointInfo(name: String((Host.current().localizedName ?? "Mac").prefix(Self.maxNameChars)), deviceType: deviceType)
+        return EndpointInfo(name: String((Host.current().localizedName ?? "Mac")), deviceType: deviceType)
         #else
-        return EndpointInfo(name: String(Device.current.description.withoutBracketedContent.prefix(Self.maxNameChars)), deviceType: deviceType)
+        return EndpointInfo(name: String(Device.current.description.withoutBracketedContent), deviceType: deviceType)
         #endif
     }
     

NearbyShare/Model/DataModel.swift

@@ -182,14 +182,15 @@ public struct EndpointInfo {
     var name: String?
     let deviceType: RemoteDeviceInfo.DeviceType
     let qrCodeData: Data?
-
     
+    static let maxNameChars = 32
+
     init(name: String, deviceType: RemoteDeviceInfo.DeviceType) {
-        self.name = name
+        self.name = String(decoding: Self.sanitizedString(name), as: UTF8.self)
         self.deviceType = deviceType
         self.qrCodeData = nil
     }
-
+    
     
     init?(data: Data) {
         guard data.count > 17 else {
@@ -254,19 +255,30 @@ public struct EndpointInfo {
         var endpointInfo: [UInt8] = [UInt8(deviceType.rawValue << 1)]
         // 16 bytes: unknown random bytes
         for _ in 0 ... 15 {
-            endpointInfo.append(UInt8.random(in: 0 ... 255))
+            endpointInfo.append(UInt8.random(in: 0...255))
         }
         // Device name in UTF-8 prefixed with 1-byte length
-        var nameChars = [UInt8]((name ?? "").utf8)
-        if nameChars.count > 255 {
-            nameChars = [UInt8](nameChars[0 ..< 255])
-        }
+        let nameChars = Self.sanitizedString(self.name ?? "")
         endpointInfo.append(UInt8(nameChars.count))
         for ch in nameChars {
             endpointInfo.append(UInt8(ch))
         }
         return Data(endpointInfo)
     }
+    
+    
+    private static func sanitizedString(_ string: String) -> [UInt8] {
+        var out: [UInt8] = []
+        out.reserveCapacity(min(Self.maxNameChars, string.utf8.count))
+
+        for scalar in string.unicodeScalars {
+            let bytes = Array(scalar.utf8)
+            if out.count + bytes.count > Self.maxNameChars { break }
+            out.append(contentsOf: bytes)
+        }
+
+        return out
+    }
 }
 
 

QuickDrop/View/ChangeDeviceNameModifier.swift

@@ -12,18 +12,11 @@ struct ChangeDeviceNameAlertModifier: ViewModifier {
     @Binding var isPresented: Bool
     @State var customName = ""
     
-    let maxLength = NearbyConnectionManager.maxNameChars
-    
     func body(content: Content) -> some View {
         
         content
             .alert("ChangeDeviceName", isPresented: $isPresented) {
                 TextField("DeviceName", text: $customName)
-                    .onChange(of: customName) { newValue in
-                        if newValue.count > maxLength {
-                            customName = String(newValue.prefix(maxLength))
-                        }
-                    }
                 
                 Button("Save") {
                     let trimmed = customName.trimmingCharacters(in: .whitespacesAndNewlines)