Move Base64 codec into a helper module.

src/helpers.rs

@@ -0,0 +1,21 @@
+// Copyright (c) 2017 Emmanuel Gil Peyrot <linkmauve@linkmauve.fr>
+//
+// 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/.
+
+use base64;
+use error::Error;
+
+/// Codec wrapping base64 encode/decode
+pub struct Base64;
+
+impl Base64 {
+    pub fn decode(s: &str) -> Result<Vec<u8>, Error> {
+        Ok(base64::decode(s)?)
+    }
+
+    pub fn encode(b: &Vec<u8>) -> String {
+        base64::encode(b)
+    }
+}