unfork DDC's copy of most SDK libraries

pkg/dev_compiler/tool/input_sdk/lib/convert/codec.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.convert;
-
-/**
- * A [Codec] encodes and (if supported) decodes data.
- *
- * Codecs can be fused. For example fusing [JSON] and [UTF8] produces
- * an encoder that can convert Json objects directly to bytes, or can decode
- * bytes directly to json objects.
- *
- * Fused codecs generally attempt to optimize the operations and can be faster
- * than executing each step of an encoding separately.
- *
- * *Codecs are still experimental and are subject to change without notice.*
- */
-abstract class Codec<S, T> {
-  const Codec();
-
-  T encode(S input) => encoder.convert(input);
-  S decode(T encoded) => decoder.convert(encoded);
-
-  /**
-   * Returns the encoder from [S] to [T].
-   *
-   * It may be stateful and should not be reused.
-   */
-  Converter<S, T> get encoder;
-  /**
-   * Returns the decoder of `this`, converting from [T] to [S].
-   *
-   * It may be stateful an should not be reused.
-   */
-  Converter<T, S> get decoder;
-
-  /**
-   * Fuses `this` with `other`.
-   *
-   * When encoding, the resulting codec encodes with `this` before
-   * encoding with [other].
-   *
-   * When decoding, the resulting codec decodes with [other] before decoding
-   * with `this`.
-   *
-   * In some cases one needs to use the [inverted] codecs to be able to fuse
-   * them correctly. That is, the output type of `this` ([T]) must match the
-   * input type of the second codec [other].
-   *
-   * Examples:
-   *
-   *     final JSON_TO_BYTES = JSON.fuse(UTF8);
-   *     List<int> bytes = JSON_TO_BYTES.encode(["json-object"]);
-   *     var decoded = JSON_TO_BYTES.decode(bytes);
-   *     assert(decoded is List && decoded[0] == "json-object");
-   *
-   *     var inverted = JSON.inverted;
-   *     var jsonIdentity = JSON.fuse(inverted);
-   *     var jsonObject = jsonIdentity.encode(["1", 2]);
-   *     assert(jsonObject is List && jsonObject[0] == "1" && jsonObject[1] == 2);
-   */
-  // TODO(floitsch): use better example with line-splitter once that one is
-  // in this library.
-  Codec<S, dynamic/*=R*/> fuse/*<R>*/(Codec<T, dynamic/*=R*/> other) {
-    return new _FusedCodec<S, T, dynamic/*=R*/>(this, other);
-  }
-
-  /**
-   * Inverts `this`.
-   *
-   * The [encoder] and [decoder] of the resulting codec are swapped.
-   */
-  Codec<T, S> get inverted => new _InvertedCodec<T, S>(this);
-}
-
-/**
- * Fuses the given codecs.
- *
- * In the non-chunked conversion simply invokes the non-chunked conversions in
- * sequence.
- */
-class _FusedCodec<S, M, T> extends Codec<S, T> {
-  final Codec<S, M> _first;
-  final Codec<M, T> _second;
-
-  Converter<S, T> get encoder => _first.encoder.fuse/*<T>*/(_second.encoder);
-  Converter<T, S> get decoder => _second.decoder.fuse/*<S>*/(_first.decoder);
-
-  _FusedCodec(this._first, this._second);
-}
-
-class _InvertedCodec<T, S> extends Codec<T, S> {
-  final Codec<S, T> _codec;
-
-  _InvertedCodec(Codec<S, T> codec) : _codec = codec;
-
-  Converter<T, S> get encoder => _codec.decoder;
-  Converter<S, T> get decoder => _codec.encoder;
-
-  Codec<S, T> get inverted => _codec;
-}