add swift flatbuffers

flatbuffers/Mutable.swift

@@ -0,0 +1,88 @@
+/*
+ * Copyright 2023 Google Inc. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#if !os(WASI)
+import Foundation
+#else
+import SwiftOverlayShims
+#endif
+
+/// Mutable is a protocol that allows us to mutate Scalar values within a ``ByteBuffer``
+public protocol Mutable {
+  /// makes Flatbuffer accessed within the Protocol
+  var bb: ByteBuffer { get }
+  /// makes position of the ``Table``/``struct`` accessed within the Protocol
+  var postion: Int32 { get }
+}
+
+extension Mutable {
+
+  /// Mutates the memory in the buffer, this is only called from the access function of ``Table`` and ``struct``
+  /// - Parameters:
+  ///   - value: New value to be inserted to the buffer
+  ///   - index: index of the Element
+  func mutate<T: Scalar>(value: T, o: Int32) -> Bool {
+    guard o != 0 else { return false }
+    bb.write(value: value, index: Int(o), direct: true)
+    return true
+  }
+}
+
+extension Mutable where Self == Table {
+
+  /// Mutates a value by calling mutate with respect to the position in a ``Table``
+  /// - Parameters:
+  ///   - value: New value to be inserted to the buffer
+  ///   - index: index of the Element
+  public func mutate<T: Scalar>(_ value: T, index: Int32) -> Bool {
+    guard index != 0 else { return false }
+    return mutate(value: value, o: index + postion)
+  }
+
+  /// Directly mutates the element by calling mutate
+  ///
+  /// Mutates the Element at index ignoring the current position by calling mutate
+  /// - Parameters:
+  ///   - value: New value to be inserted to the buffer
+  ///   - index: index of the Element
+  public func directMutate<T: Scalar>(_ value: T, index: Int32) -> Bool {
+    mutate(value: value, o: index)
+  }
+}
+
+extension Mutable where Self == Struct {
+
+  /// Mutates a value by calling mutate with respect to the position in the struct
+  /// - Parameters:
+  ///   - value: New value to be inserted to the buffer
+  ///   - index: index of the Element
+  public func mutate<T: Scalar>(_ value: T, index: Int32) -> Bool {
+    mutate(value: value, o: index + postion)
+  }
+
+  /// Directly mutates the element by calling mutate
+  ///
+  /// Mutates the Element at index ignoring the current position by calling mutate
+  /// - Parameters:
+  ///   - value: New value to be inserted to the buffer
+  ///   - index: index of the Element
+  public func directMutate<T: Scalar>(_ value: T, index: Int32) -> Bool {
+    mutate(value: value, o: index)
+  }
+}
+
+extension Struct: Mutable {}
+extension Table: Mutable {}