First version of Codecs and Converters.

sdk/lib/codec/encoding.dart

+// Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+part of dart.codec;
+
+/**
+ * Open-ended Encoding enum.
+ */
+// TODO(floitsch): dart:io already has an Encoding class. If we can't
+// consolitate them, we need to remove `Encoding` here.
+abstract class Encoding extends Codec<String, List<int>> {
+  const Encoding();
+}
+
+// TODO(floitsch): add other encodings, like ASCII and ISO_8859_1.
+const UTF8 = const Utf8Codec();
+
+/**
+ * A [Utf8Codec] encodes strings to utf-8 code units (bytes) and decodes
+ * UTF-8 code units to strings.
+ */
+// TODO(floitsch): Needs a way to specify if decoding should throw or use
+// the replacement character.
+class Utf8Codec extends Encoding {
+  const Utf8Codec();
+
+  Converter<String, List<int>> get encoder => new Utf8Encoder();
+  Converter<List<int>, String> get decoder => new Utf8Decoder();
+}