#161 Add DataConvertible to ATTReadByTypeRequest

Sources/BluetoothGATT/ATTReadByTypeRequest.swift

@@ -6,16 +6,16 @@
 //  Copyright © 2018 PureSwift. All rights reserved.
 //
 
-import Foundation
+import Bluetooth
 
 /// Read By Type Request
 ///
 /// The *Read By Type Request* is used to obtain the values of attributes where the
 /// attribute type is known but the handle is not known.
 @frozen
-public struct ATTReadByTypeRequest: ATTProtocolDataUnit, Equatable {
+public struct ATTReadByTypeRequest: ATTProtocolDataUnit, Equatable, Hashable, Sendable {
 
-    public static var attributeOpcode: ATTOpcode { return .readByTypeRequest }
+    public static var attributeOpcode: ATTOpcode { .readByTypeRequest }
 
     /// First requested handle number
     public var startHandle: UInt16
@@ -26,24 +26,26 @@ public struct ATTReadByTypeRequest: ATTProtocolDataUnit, Equatable {
     /// 2 or 16 octet UUID
     public var attributeType: BluetoothUUID
 
-    public init(startHandle: UInt16,
-                endHandle: UInt16,
-                attributeType: BluetoothUUID) {
-
-        assert(attributeType.length != .bit32, "32-bit UUID not supported")
-
+    public init(
+        startHandle: UInt16,
+        endHandle: UInt16,
+        attributeType: BluetoothUUID
+    ) {
+        assert(attributeType.dataLength != 4, "32-bit UUID not supported")
         self.startHandle = startHandle
         self.endHandle = endHandle
         self.attributeType = attributeType
     }
 }
 
-public extension ATTReadByTypeRequest {
+// MARK: - DataConvertible
+
+extension ATTReadByTypeRequest: DataConvertible {
 
-    init?(data: Data) {
+    public init?<Data: DataContainer>(data: Data) {
 
         guard let length = Length(rawValue: data.count),
-            type(of: self).validateOpcode(data)
+            Self.validateOpcode(data)
             else { return nil }
 
         self.startHandle = UInt16(littleEndian: UInt16(bytes: (data[1], data[2])))
@@ -54,31 +56,19 @@ public extension ATTReadByTypeRequest {
             let value = UInt16(littleEndian: UInt16(bytes: (data[5], data[6])))
             self.attributeType = .bit16(value)
         case .uuid128:
-            self.attributeType = BluetoothUUID(littleEndian: BluetoothUUID(data: data.suffixNoCopy(from: 5))!)
+            self.attributeType = BluetoothUUID(littleEndian: BluetoothUUID(data: data.subdata(in: 5 ..< length.rawValue))!)
         }
     }
 
-    var data: Data {
-
-        return Data(self)
-    }
-}
-
-// MARK: - DataConvertible
-
-extension ATTReadByTypeRequest: DataConvertible {
-
-    var dataLength: Int {
-
-        return length.rawValue
+    public func append<Data>(to data: inout Data) where Data : DataContainer {
+        data += Self.attributeOpcode.rawValue
+        data += self.startHandle.littleEndian
+        data += self.endHandle.littleEndian
+        data += self.attributeType.littleEndian
     }
 
-    static func += <T: DataContainer> (data: inout T, value: ATTReadByTypeRequest) {
-
-        data += attributeOpcode.rawValue
-        data += value.startHandle.littleEndian
-        data += value.endHandle.littleEndian
-        data += value.attributeType.littleEndian
+    public var dataLength: Int {
+        length.rawValue
     }
 }
 
@@ -93,11 +83,13 @@ internal extension ATTReadByTypeRequest {
     }
 
     private var length: Length {
-
         switch attributeType {
-        case .bit16: return .uuid16
-        case .bit128: return .uuid128
-        case .bit32: fatalError() // FIXME: Do not allow 32-bit UUID for Blueooth LE
+        case .bit16:
+            return .uuid16
+        case .bit128:
+            return .uuid128
+        case .bit32:
+            fatalError() // Do not allow 32-bit UUID for Blueooth LE
         }
     }
 }