Fix crash in BinaryDataDecoder when decoding float values from misali…

…gned memory. (#59)

The crash error was "load from misaligned raw pointer".

Sources/BinaryCodable/BinaryDataCoders/BinaryDataDecoder.swift

@@ -111,10 +111,13 @@ private class BinaryDataDecodingContainer: BinaryDecodingContainer {
       throw BinaryDecodingError.dataCorrupted(.init(debugDescription:
         "Not enough data to create a a type of \(type). Needed: \(byteWidth). Received: \(bytes.count)."))
     }
-    let value = bytes.withUnsafeBytes { ptr -> T in
-      return ptr.load(as: T.self)
+    return bytes.withUnsafeBytes { ptr in
+      var value: T = 0
+      withUnsafeMutableBytes(of: &value) { valuePtr in
+        valuePtr.copyMemory(from: UnsafeRawBufferPointer(rebasing: ptr[0..<ptr.count]))
+      }
+      return value
     }
-    return value
   }
 
   func decode<T: FixedWidthInteger>(_ type: T.Type) throws -> T {

Tests/BinaryCodableTests/MisalignedDecoderTests.swift

@@ -15,7 +15,7 @@
 import BinaryCodable
 import XCTest
 
-private struct MisalignedPacket: BinaryDecodable {
+private struct MisalignedUInt16Packet: BinaryDecodable {
   let twoByteInt: UInt16
   init(from decoder: BinaryDecoder) throws {
     var container = decoder.container(maxLength: nil)
@@ -24,17 +24,38 @@ private struct MisalignedPacket: BinaryDecodable {
   }
 }
 
+private struct MisalignedFloatPacket: BinaryDecodable {
+  let fourByteFloat: Float
+  init(from decoder: BinaryDecoder) throws {
+    var container = decoder.container(maxLength: nil)
+    _ = try container.decode(length: 1)
+    self.fourByteFloat = try container.decode(Float.self)
+  }
+}
+
 final class MisalignedDecoderTests: XCTestCase {
 
-  func testEmpty() throws {
+  func testUInt16() throws {
     // Given
     let packetData: [UInt8] = [0, 3, 0]
     let decoder = BinaryDataDecoder()
 
     // When
-    let packet = try decoder.decode(MisalignedPacket.self, from: packetData)
+    let packet = try decoder.decode(MisalignedUInt16Packet.self, from: packetData)
 
     // Then
     XCTAssertEqual(packet.twoByteInt, 3)
   }
+
+  func testFloat() throws {
+    // Given
+    let packetData: [UInt8] = [0, 0, 0, 0x80, 0x3f]
+    let decoder = BinaryDataDecoder()
+
+    // When
+    let packet = try decoder.decode(MisalignedFloatPacket.self, from: packetData)
+
+    // Then
+    XCTAssertEqual(packet.fourByteFloat, 1.0, accuracy: 0.001)
+  }
 }