Dactyloidae iOS initial commit

mobile/ios/Shared/Bytes.swift

@@ -0,0 +1,49 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+import Foundation
+
+public typealias GUID = String
+
+/**
+ * Utilities for futzing with bytes and such.
+ */
+open class Bytes {
+    open class func generateRandomBytes(_ len: UInt) -> Data {
+        let len = Int(len)
+        var data = Data(count: len)
+        data.withUnsafeMutableBytes { (p: UnsafeMutablePointer<UInt8>) in
+            if (SecRandomCopyBytes(kSecRandomDefault, len, p) != errSecSuccess) {
+                fatalError("Random byte generation failed.")
+            }
+        }
+        return data
+    }
+
+    open class func generateGUID() -> GUID {
+        // Turns the standard NSData encoding into the URL-safe variant that Sync expects.
+        return generateRandomBytes(9)
+            .base64EncodedString(options: NSData.Base64EncodingOptions())
+            .replacingOccurrences(of: "/", with: "_", options: NSString.CompareOptions(), range: nil)
+            .replacingOccurrences(of: "+", with: "-", options: NSString.CompareOptions(), range: nil)
+    }
+
+    open class func decodeBase64(_ b64: String) -> Data? {
+        return Data(base64Encoded: b64,
+                      options: NSData.Base64DecodingOptions())
+    }
+
+    /**
+     * Turn a string of base64 characters into an NSData *without decoding*.
+     * This is to allow HMAC to be computed of the raw base64 string.
+     */
+    open class func dataFromBase64(_ b64: String) -> Data? {
+        return b64.data(using: String.Encoding.ascii, allowLossyConversion: false)
+    }
+
+    func fromHex(_ str: String) -> Data {
+       // TODO
+        return Data()
+    }
+}