dart:convert library.

sdk/lib/codec/codec.dart

Index: sdk/lib/codec/codec.dart
diff --git a/sdk/lib/codec/codec.dart b/sdk/lib/codec/codec.dart
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+// 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.
+
+library dart.codec;
+
+import 'dart:convert';
+
+part 'encoding.dart';
+part 'json.dart';
+part 'line_splitter.dart';
+
+abstract class Codec<S, T> {
+  const Codec();
+
+  T encode(S input) => encoder.convert(input);
+  S decode(T encoded) => decoder.convert(encoded);
+
+  Converter<S, T> get encoder;
+  Converter<T, S> get decoder;
+
+  Codec<S, dynamic> fuse(Codec<T, dynamic> other) {
+    return new FusedCodec<S, T, dynamic>(this, other);
+  }
+}
+
+class FusedCodec<S, M, T> extends Codec<S, T> {
+  final Codec<S, M> first;
+  final Codec<M, T> second;
+
+  Converter get encoder => first.encoder.fuse(second.encoder);
+  Converter get decoder => second.decoder.fuse(first.decoder);
+
+  FusedCodec(Codec<S, M> first, Codec<M, T> second)
+      : this.first = first,
+        this.second = second;
+}
+
+class InvertedCodec<S, T> extends Codec<S, T> {
+  final Codec<T, S> _codec;
+
+  InvertedCodec(Codec<T, S> codec) : _codec = codec;
+
+  Converter get encoder => _codec.decoder;
+  Converter get decoder => _codec.encoder;
+}