add swift flatbuffers

flatbuffers/FbConstants.swift

@@ -0,0 +1,122 @@
+/*
+ * 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)
+#if os(Linux)
+import CoreFoundation
+#else
+import Foundation
+#endif
+#else
+import SwiftOverlayShims
+#endif
+
+/// A boolean to see if the system is littleEndian
+let isLitteEndian: Bool = {
+  let number: UInt32 = 0x12345678
+  return number == number.littleEndian
+}()
+/// Constant for the file id length
+let FileIdLength = 4
+/// Type aliases
+public typealias Byte = UInt8
+public typealias UOffset = UInt32
+public typealias SOffset = Int32
+public typealias VOffset = UInt16
+/// Maximum size for a buffer
+public let FlatBufferMaxSize = UInt32
+  .max << ((MemoryLayout<SOffset>.size * 8 - 1) - 1)
+
+/// Protocol that All Scalars should conform to
+///
+/// Scalar is used to conform all the numbers that can be represented in a FlatBuffer. It's used to write/read from the buffer.
+public protocol Scalar: Equatable {
+  associatedtype NumericValue
+  var convertedEndian: NumericValue { get }
+}
+
+extension Scalar where Self: Verifiable {}
+
+extension Scalar where Self: FixedWidthInteger {
+  /// Converts the value from BigEndian to LittleEndian
+  ///
+  /// Converts values to little endian on machines that work with BigEndian, however this is NOT TESTED yet.
+  public var convertedEndian: NumericValue {
+    self as! Self.NumericValue
+  }
+}
+
+extension Double: Scalar, Verifiable {
+  public typealias NumericValue = UInt64
+
+  public var convertedEndian: UInt64 {
+    bitPattern.littleEndian
+  }
+}
+
+extension Float32: Scalar, Verifiable {
+  public typealias NumericValue = UInt32
+
+  public var convertedEndian: UInt32 {
+    bitPattern.littleEndian
+  }
+}
+
+extension Bool: Scalar, Verifiable {
+  public var convertedEndian: UInt8 {
+    self == true ? 1 : 0
+  }
+
+  public typealias NumericValue = UInt8
+}
+
+extension Int: Scalar, Verifiable {
+  public typealias NumericValue = Int
+}
+
+extension Int8: Scalar, Verifiable {
+  public typealias NumericValue = Int8
+}
+
+extension Int16: Scalar, Verifiable {
+  public typealias NumericValue = Int16
+}
+
+extension Int32: Scalar, Verifiable {
+  public typealias NumericValue = Int32
+}
+
+extension Int64: Scalar, Verifiable {
+  public typealias NumericValue = Int64
+}
+
+extension UInt8: Scalar, Verifiable {
+  public typealias NumericValue = UInt8
+}
+
+extension UInt16: Scalar, Verifiable {
+  public typealias NumericValue = UInt16
+}
+
+extension UInt32: Scalar, Verifiable {
+  public typealias NumericValue = UInt32
+}
+
+extension UInt64: Scalar, Verifiable {
+  public typealias NumericValue = UInt64
+}
+
+public func FlatBuffersVersion_23_5_26() {}