content: // 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 [Converter] converts data from one representation into another.
   *
   * *Converters are still experimental and are subject to change without notice.*
   *
   */
  abstract class Converter<S, T> implements StreamTransformer {
    const Converter();
  
    /**
     * Converts [input] and returns the result of the conversion.
     */
    T convert(S input);
  
    /**
     * Fuses `this` with [other].
     *
     * Encoding with the resulting converter is equivalent to converting with
     * `this` before converting with `other`.
     */
    Converter<S, dynamic> fuse(Converter<T, dynamic> other) {
      return new _FusedConverter<S, T, dynamic>(this, other);
    }
  
    /**
     * Starts a chunked conversion.
     */
    ChunkedConversionSink startChunkedConversion(ChunkedConversionSink sink) {
      throw new UnsupportedError(
          "This converter does not support chunked conversions: $this");
    }
  
    // Subclasses are encouraged to provide better types.
    Stream bind(Stream source) {
      return new Stream.eventTransformed(
          source,
          (EventSink sink) => new _ConverterStreamEventSink(this, sink));
    }
  }
  
  /**
   * Fuses two converters.
   *
   * For a non-chunked conversion converts the input in sequence.
   */
  class _FusedConverter<S, M, T> extends Converter<S, T> {
    final Converter _first;
    final Converter _second;
  
    _FusedConverter(this._first, this._second);
  
    T convert(S input) => _second.convert(_first.convert(input));
  
    ChunkedConversionSink startChunkedConversion(ChunkedConversionSink sink) {
      return _first.startChunkedConversion(_second.startChunkedConversion(sink));
    }
  }
  