Updates the TensorFlow Lite Swift library to Swift 5.

PiperOrigin-RevId: 245493147

tensorflow/lite/experimental/swift/Sources/Interpreter.swift

@@ -87,7 +87,6 @@ public final class Interpreter {
   /// - Throws: An error if the model was not ready because tensors were not allocated.
   public func invoke() throws {
     guard TFL_InterpreterInvoke(cInterpreter) == kTfLiteOk else {
-      // TODO(b/117510052): Determine which error to throw.
       throw InterpreterError.allocateTensorsRequired
     }
   }
@@ -124,7 +123,6 @@ public final class Interpreter {
     let zeroPoint = Int(cQuantizationParams.zero_point)
     var quantizationParameters: QuantizationParameters? = nil
     if scale != 0.0 {
-      // TODO(b/117510052): Update this check once the TfLiteQuantizationParams struct has a mode.
       quantizationParameters = QuantizationParameters(scale: scale, zeroPoint: zeroPoint)
     }
     let tensor = Tensor(
@@ -154,7 +152,6 @@ public final class Interpreter {
       let bytes = TFL_TensorData(cTensor),
       let nameCString = TFL_TensorName(cTensor)
     else {
-      // TODO(b/117510052): Determine which error to throw.
       throw InterpreterError.invokeInterpreterRequired
     }
     guard let dataType = TensorDataType(type: TFL_TensorType(cTensor)) else {
@@ -172,7 +169,6 @@ public final class Interpreter {
     let zeroPoint = Int(cQuantizationParams.zero_point)
     var quantizationParameters: QuantizationParameters? = nil
     if scale != 0.0 {
-      // TODO(b/117510052): Update this check once the TfLiteQuantizationParams struct has a mode.
       quantizationParameters = QuantizationParameters(scale: scale, zeroPoint: zeroPoint)
     }
     let tensor = Tensor(
@@ -233,7 +229,13 @@ public final class Interpreter {
       throw InterpreterError.invalidTensorDataCount(provided: data.count, required: byteCount)
     }
 
+    #if swift(>=5.0)
+    let status = data.withUnsafeBytes {
+      TFL_TensorCopyFromBuffer(cTensor, $0.baseAddress, data.count)
+    }
+    #else
     let status = data.withUnsafeBytes { TFL_TensorCopyFromBuffer(cTensor, $0, data.count) }
+    #endif  // swift(>=5.0)
     guard status == kTfLiteOk else { throw InterpreterError.failedToCopyDataToInputTensor }
     return try input(at: index)
   }

tensorflow/lite/experimental/swift/Sources/InterpreterError.swift

@@ -68,32 +68,4 @@ extension InterpreterError: CustomStringConvertible {
   }
 }
 
-#if swift(>=4.2)
 extension InterpreterError: Equatable {}
-#else
-extension InterpreterError: Equatable {
-  public static func == (lhs: InterpreterError, rhs: InterpreterError) -> Bool {
-    switch (lhs, rhs) {
-    case (.invalidTensorDataType, .invalidTensorDataType),
-         (.failedToLoadModel, .failedToLoadModel),
-         (.failedToCreateInterpreter, .failedToCreateInterpreter),
-         (.failedToAllocateTensors, .failedToAllocateTensors),
-         (.allocateTensorsRequired, .allocateTensorsRequired),
-         (.invokeInterpreterRequired, .invokeInterpreterRequired):
-      return true
-    case (.invalidTensorIndex(let lhsIndex, let lhsMaxIndex),
-          .invalidTensorIndex(let rhsIndex, let rhsMaxIndex)):
-      return lhsIndex == rhsIndex && lhsMaxIndex == rhsMaxIndex
-    case (.invalidTensorDataCount(let lhsProvidedCount, let lhsRequiredCount),
-          .invalidTensorDataCount(let rhsProvidedCount, let rhsRequiredCount)):
-      return lhsProvidedCount == rhsProvidedCount && lhsRequiredCount == rhsRequiredCount
-    case (.failedToResizeInputTensor(let lhsIndex), .failedToResizeInputTensor(let rhsIndex)):
-      return lhsIndex == rhsIndex
-    case (.tensorFlowLiteError(let lhsMessage), .tensorFlowLiteError(let rhsMessage)):
-      return lhsMessage == rhsMessage
-    default:
-      return false
-    }
-  }
-}
-#endif  // swift(>=4.2)

tensorflow/lite/experimental/swift/TestApps/TensorFlowLiteApp/TensorFlowLiteApp/AppDelegate.swift

@@ -14,11 +14,3 @@ final class AppDelegate: UIResponder, UIApplicationDelegate {
     return true
   }
 }
-
-// MARK: - Extensions
-
-#if !swift(>=4.2)
-extension UIApplication {
-  typealias LaunchOptionsKey = UIApplicationLaunchOptionsKey
-}
-#endif  // !swift(>=4.2)

tensorflow/lite/experimental/swift/TestApps/TensorFlowLiteApp/TensorFlowLiteApp/Array+TensorFlowLite.swift

@@ -11,12 +11,15 @@ extension Array {
   /// - Parameter unsafeData: The data containing the bytes to turn into an array.
   init?(unsafeData: Data) {
     guard unsafeData.count % MemoryLayout<Element>.stride == 0 else { return nil }
-    let elements = unsafeData.withUnsafeBytes {
+    #if swift(>=5.0)
-      UnsafeBufferPointer<Element>(
+    self = unsafeData.withUnsafeBytes { .init($0.bindMemory(to: Element.self)) }
+    #else
+    self = unsafeData.withUnsafeBytes {
+      .init(UnsafeBufferPointer<Element>(
         start: $0,
         count: unsafeData.count / MemoryLayout<Element>.stride
-      )
+      ))
     }
-    self.init(elements)
+    #endif  // swift(>=5.0)
   }
 }

tensorflow/lite/experimental/swift/Tests/InterpreterTests.swift

@@ -287,18 +287,24 @@ private enum AddQuantizedModel {
 extension Array {
   /// Creates a new array from the bytes of the given unsafe data.
   ///
+  /// - Warning: The array's `Element` type must be trivial in that it can be copied bit for bit
+  ///     with no indirection or reference-counting operations; otherwise, copying the raw bytes in
+  ///     the `unsafeData`'s buffer to a new array returns an unsafe copy.
   /// - Note: Returns `nil` if `unsafeData.count` is not a multiple of
   ///     `MemoryLayout<Element>.stride`.
   /// - Parameter unsafeData: The data containing the bytes to turn into an array.
   init?(unsafeData: Data) {
     guard unsafeData.count % MemoryLayout<Element>.stride == 0 else { return nil }
-    let elements = unsafeData.withUnsafeBytes {
+    #if swift(>=5.0)
-      UnsafeBufferPointer<Element>(
+    self = unsafeData.withUnsafeBytes { .init($0.bindMemory(to: Element.self)) }
+    #else
+    self = unsafeData.withUnsafeBytes {
+      .init(UnsafeBufferPointer<Element>(
         start: $0,
         count: unsafeData.count / MemoryLayout<Element>.stride
-      )
+      ))
     }
-    self.init(elements)
+    #endif  // swift(>=5.0)
   }
 }
 

tensorflow/lite/experimental/swift/Tests/ModelTests.swift

@@ -25,8 +25,8 @@ class ModelTests: XCTestCase {
     let bundle = Bundle(for: type(of: self))
     guard let modelPath = bundle.path(
       forResource: Constant.modelInfo.name,
-            ofType: Constant.modelInfo.extension)
+      ofType: Constant.modelInfo.extension
-    else {
+    ) else {
       XCTFail("Failed to get the model file path.")
       return
     }