First version of Codecs and Converters.

sdk/lib/codec/encoding.dart

Index: sdk/lib/codec/encoding.dart
diff --git a/sdk/lib/codec/encoding.dart b/sdk/lib/codec/encoding.dart
new file mode 100644
index 0000000000000000000000000000000000000000..800c403cbab8845a96c900474107c0a34ce29436
--- /dev/null
+++ b/sdk/lib/codec/encoding.dart
@@ -0,0 +1,29 @@
+// 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.
+// TODO(floitsch): add other encodings, like ASCII and ISO_8859_1.

[Lasse Reichstein Nielsen, 2013/07/12 11:50:47]

These are partial encodings of strings (where strings are seen as UTF-16 +
unmatched surrogates).
They could be added in a package instead of here. I'd prefer to just have the
total encodings (UTF-8, UTF-16, UTF-32) in the core library, unless we see it as
a way to optimize.

[floitsch, 2013/07/12 16:09:15]

If we intend to replace the Encoding enum in dart:io we should have at least
what they are having.

+abstract class Encoding extends Codec<String, List<int>> {
+  const Encoding();
+
+  static const UTF8 = const Utf8Codec();

[Lasse Reichstein Nielsen, 2013/07/12 11:50:47]

Put this outside the class. Since it's an open-ended enum, others will have to
add other encodings, and they can't put it inside the class, so we will get the
inconsistent:
 Encoding.UTF8
but
 WIN1252
from another package.

[floitsch, 2013/07/12 16:09:15]

Done.

+}
+
+/**
+ * A [Utf8Codec] encodes strings to utf-8 codeunits (bytes) and decodes

[Lasse Reichstein Nielsen, 2013/07/12 11:50:47]

codeunits -> code units

[floitsch, 2013/07/12 16:09:15]

Done.

+ * utf-8 codeunits to strings.

[Lasse Reichstein Nielsen, 2013/07/12 11:50:47]

utf-8 -> UTF-8
codeunits -> code units

[floitsch, 2013/07/12 16:09:15]

Done.

+ */
+// TODO(floitsch): Needs a way to specify a replacement character for decoding.

[Lasse Reichstein Nielsen, 2013/07/12 11:50:47]

Default replacement character is U+FFFD (aka. REPLACEMENT CHARACTER).
Using a different replacement character is really not part of UTF-8 decoding,
but should be handled by a following character replacement step.

[floitsch, 2013/07/12 16:09:15]

Changed comment.

+class Utf8Codec extends Encoding {
+  const Utf8Codec();
+
+  Converter<String, List<int>> get encoder => new Utf8Encoder();
+  Converter<List<int>, String> get decoder => new Utf8Decoder();
+}