parseAsync method

Implementation

@override
AsyncResult<int> parseAsync(State<ChunkedData<StringReader>> state) {
  final result = AsyncResult<int>();
  if (!backtrack(state)) {
    result.ok = false;
    return result;
  }

  final input = state.input;
  final start = input.start;
  input.buffering++;

  final data = input.data;
  final end = input.end;
  int? c;
  if (state.pos < end) {
    input.buffering--;
    final source = data.source;
    c = source.runeAt(state.pos - start);
    if (result.ok = f(c)) {
      state.pos += c > 0xffff ? 2 : 1;
      result.value = Result(c);
    } else {
      state.fail<Object?>(ErrorUnexpectedCharacter(c));
    }

    input.handler = result.handler;
    return result;
  }

  void parse() {
    final data = input.data;
    final end = input.end;
    if (state.pos >= end && !input.isClosed) {
      input.sleep = true;
      input.handler = parse;
      return;
    }

    input.buffering--;
    int? c;
    if (state.pos < end) {
      final source = data.source;
      c = source.runeAt(state.pos - start);
      if (f(c)) {
        state.pos += c > 0xffff ? 2 : 1;
        result.value = Result(c);
        result.ok = true;
        input.handler = result.handler;
        return;
      }
    }

    result.ok = false;
    state.fail<Object?>(ErrorUnexpectedCharacter(c));
    input.handler = result.handler;
  }

  parse();
  return result;
}