protected override async ValueTask <bool> MoveNextCore()
{
switch (_state)
{
case AsyncIteratorState.Allocated:
_buffer = await _source.ToArrayAsync(_cancellationToken).ConfigureAwait(false); // TODO: Use buffer.
_minIndexIterator = _minIndexInclusive;
_maxIndexIterator = _maxIndexInclusive;
var count = _buffer.Length;
if (count > _minIndexIterator)
{
if (count <= _maxIndexIterator)
{
_maxIndexIterator = count - 1;
}
var sorter = _source.GetAsyncEnumerableSorter(_cancellationToken);
if (_minIndexIterator == _maxIndexIterator)
{
_current = await sorter.ElementAt(_buffer, _buffer.Length, _minIndexIterator).ConfigureAwait(false);
_minIndexIterator = int.MaxValue;
_maxIndexIterator = int.MinValue;
_state = AsyncIteratorState.Iterating;
return(true);
}
else
{
_indexes = await sorter.Sort(_buffer, _buffer.Length, _minIndexIterator, _maxIndexIterator).ConfigureAwait(false);
}
_state = AsyncIteratorState.Iterating;
goto case AsyncIteratorState.Iterating;
}
await DisposeAsync();
break;
case AsyncIteratorState.Iterating:
if (_minIndexIterator <= _maxIndexIterator)
{
_current = _buffer[_indexes[_minIndexIterator++]];
return(true);
}
await DisposeAsync().ConfigureAwait(false);
break;
}
return(false);
}
internal override AsyncEnumerableSorter <TElement> GetAsyncEnumerableSorter(AsyncEnumerableSorter <TElement> next, CancellationToken cancellationToken)
{
var sorter = new AsyncKeySelectorAsyncEnumerableSorterWithCancellation <TElement, TKey>(_keySelector, _comparer, _descending, next, cancellationToken);
if (_parent != null)
{
return(_parent.GetAsyncEnumerableSorter(sorter, cancellationToken));
}
return(sorter);
}