Fix crash in BinaryDataDecoder when decoding values from misaligned memory.

Sources/BinaryCodable/BinaryDataCoders/BinaryDataDecoder.swift

@@ -124,10 +124,13 @@ 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 decodeString(encoding: String.Encoding, terminator: UInt8?) throws -> String {

Tests/BinaryCodableTests/MisalignedDecoderTests.swift

@@ -0,0 +1,40 @@
+// Copyright 2020-present the BinaryCodable authors. 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 BinaryCodable
+import XCTest
+
+private struct MisalignedPacket: BinaryDecodable {
+  let twoByteInt: UInt16
+  init(from decoder: BinaryDecoder) throws {
+    var container = decoder.container(maxLength: nil)
+    _ = try container.decode(length: 1)
+    self.twoByteInt = try container.decode(UInt16.self)
+  }
+}
+
+final class MisalignedDecoderTests: XCTestCase {
+
+  func testEmpty() throws {
+    // Given
+    let packetData: [UInt8] = [0, 3, 0]
+    let decoder = BinaryDataDecoder()
+
+    // When
+    let packet = try decoder.decode(MisalignedPacket.self, from: packetData)
+
+    // Then
+    XCTAssertEqual(packet.twoByteInt, 3)
+  }
+}