Offical Swift port for FlexBuffers

This is the offical port for FlexBuffers within
swift, and it introcudes a Common Module where code
is shared between flatbuffers and flexbuffers.

Writing most supported values like maps, vectors,
nil and scalars into a flexbuffer buffer. And includes
tests to verify that its similar to cpp

Package.swift

@@ -27,10 +27,21 @@ let package = Package(
     .library(
       name: "FlatBuffers",
       targets: ["FlatBuffers"]),
+    .library(
+      name: "FlexBuffers",
+      targets: ["FlexBuffers"]),
   ],
   targets: [
     .target(
       name: "FlatBuffers",
+      dependencies: ["Common"],
+      path: "swift/Sources/FlatBuffers"),
+    .target(
+      name: "FlexBuffers",
+      dependencies: ["Common"],
+      path: "swift/Sources/FlexBuffers"),
+    .target(
+      name: "Common",
       dependencies: [],
-      path: "swift/Sources"),
+      path: "swift/Sources/Common"),
   ])

swift/Sources/Common/Constants.swift

@@ -0,0 +1,103 @@
+/*
+ * Copyright 2024 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.
+ */
+
+import Foundation
+
+/// A boolean to see if the system is littleEndian
+public let isLitteEndian: Bool = {
+  let number: UInt32 = 0x12345678
+  return number == number.littleEndian
+}()
+
+/// Constant for the file id length
+public let FileIdLength = 4
+
+/// 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: 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 {
+  public typealias NumericValue = UInt64
+
+  public var convertedEndian: UInt64 {
+    bitPattern.littleEndian
+  }
+}
+
+extension Float32: Scalar {
+  public typealias NumericValue = UInt32
+
+  public var convertedEndian: UInt32 {
+    bitPattern.littleEndian
+  }
+}
+
+extension Bool: Scalar {
+  public var convertedEndian: UInt8 {
+    self == true ? 1 : 0
+  }
+
+  public typealias NumericValue = UInt8
+}
+
+extension Int: Scalar {
+  public typealias NumericValue = Int
+}
+
+extension Int8: Scalar {
+  public typealias NumericValue = Int8
+}
+
+extension Int16: Scalar {
+  public typealias NumericValue = Int16
+}
+
+extension Int32: Scalar {
+  public typealias NumericValue = Int32
+}
+
+extension Int64: Scalar {
+  public typealias NumericValue = Int64
+}
+
+extension UInt8: Scalar {
+  public typealias NumericValue = UInt8
+}
+
+extension UInt16: Scalar {
+  public typealias NumericValue = UInt16
+}
+
+extension UInt32: Scalar {
+  public typealias NumericValue = UInt32
+}
+
+extension UInt64: Scalar {
+  public typealias NumericValue = UInt64
+}

swift/Sources/FlatBuffers/Int+extension.swift → swift/Sources/Common/Int+extension.swift

@@ -22,9 +22,9 @@ extension Int {
   ///
   /// This is used since the UnsafeMutableRawPointer will face issues when writing/reading
   /// if the buffer alignment exceeds that actual size of the buffer
-  var convertToPowerofTwo: Int {
+  public var convertToPowerofTwo: Int {
     guard self > 0 else { return 1 }
-    var n = UOffset(self)
+    var n = UInt32(self)
 
     #if arch(arm) || arch(i386)
     let max = UInt32(Int.max)

swift/Sources/Common/functions.swift

@@ -0,0 +1,29 @@
+/*
+ * Copyright 2024 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.
+ */
+
+import Foundation
+
+/// Gets the padding for the current element
+/// - Parameters:
+///   - bufSize: Current size of the buffer + the offset of the object to be written
+///   - elementSize: Element size
+@inline(__always)
+public func padding(
+  bufSize: UInt,
+  elementSize: UInt) -> UInt
+{
+  ((~bufSize) &+ 1) & (elementSize &- 1)
+}

swift/Sources/FlatBuffers/ByteBuffer.swift

@@ -14,6 +14,7 @@
  * limitations under the License.
  */
 
+import Common
 import Foundation
 
 /// `ByteBuffer` is the interface that stores the data for a `Flatbuffers` object

swift/Sources/FlatBuffers/Constants.swift

@@ -14,15 +14,9 @@
  * limitations under the License.
  */
 
+@_exported import Common
 import Foundation
 
-/// 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
@@ -35,80 +29,31 @@ public let FlatBufferMaxSize = UInt32
 /// 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
-}
+
+extension Scalar where Self: FixedWidthInteger {}
+
+extension Double: Verifiable {}
+
+extension Float32: Verifiable {}
+
+extension Bool: Verifiable {}
+
+extension Int: Verifiable {}
+
+extension Int8: Verifiable {}
+
+extension Int16: Verifiable {}
+
+extension Int32: Verifiable {}
+
+extension Int64: Verifiable {}
+
+extension UInt8: Verifiable {}
+
+extension UInt16: Verifiable {}
+
+extension UInt32: Verifiable {}
+
+extension UInt64: Verifiable {}
 
 public func FlatBuffersVersion_25_2_10() {}

swift/Sources/FlatBuffers/FlatBufferBuilder.swift

@@ -14,6 +14,7 @@
  * limitations under the License.
  */
 
+import Common
 import Foundation
 
 /// ``FlatBufferBuilder`` builds a `FlatBuffer` through manipulating its internal state.
@@ -343,19 +344,6 @@ public struct FlatBufferBuilder {
     }
   }
 
-  /// Gets the padding for the current element
-  /// - Parameters:
-  ///   - bufSize: Current size of the buffer + the offset of the object to be written
-  ///   - elementSize: Element size
-  @inline(__always)
-  @usableFromInline
-  mutating internal func padding(
-    bufSize: UInt32,
-    elementSize: UInt32) -> UInt32
-  {
-    ((~bufSize) &+ 1) & (elementSize &- 1)
-  }
-
   /// Prealigns the buffer before writting a new object into the buffer
   /// - Parameters:
   ///   - len:Length of the object
@@ -364,11 +352,9 @@ public struct FlatBufferBuilder {
   @usableFromInline
   mutating internal func preAlign(len: Int, alignment: Int) {
     minAlignment(size: alignment)
-    _bb.fill(
-      padding: Int(
-        padding(
-          bufSize: _bb.size &+ UOffset(len),
-          elementSize: UOffset(alignment))))
+    _bb.fill(padding: numericCast(padding(
+      bufSize: numericCast(_bb.size) &+ numericCast(len),
+      elementSize: numericCast(alignment))))
   }
 
   /// Prealigns the buffer before writting a new object into the buffer

swift/Sources/FlatBuffers/Table.swift

@@ -14,6 +14,7 @@
  * limitations under the License.
  */
 
+import Common
 import Foundation
 
 /// `Table` is a Flatbuffers object that can read,