using System.Collections.Generic; namespace System.Linq { internal class OrderedSequence<TElement, TKey> : OrderedEnumerable<TElement> { private OrderedEnumerable<TElement> parent; private Func<TElement, TKey> selector; private IComparer<TKey> comparer; private SortDirection direction; internal OrderedSequence(IEnumerable<TElement> source, Func<TElement, TKey> key_selector, IComparer<TKey> comparer, SortDirection direction) : base(source) { selector = key_selector; this.comparer = (comparer ?? Comparer<TKey>.Default); this.direction = direction; } internal OrderedSequence(OrderedEnumerable<TElement> parent, IEnumerable<TElement> source, Func<TElement, TKey> keySelector, IComparer<TKey> comparer, SortDirection direction) : this(source, keySelector, comparer, direction) { this.parent = parent; } public override SortContext<TElement> CreateContext(SortContext<TElement> current) { SortContext<TElement> sortContext = new SortSequenceContext<TElement, TKey>(selector, comparer, direction, current); if (parent != null) return parent.CreateContext(sortContext); return sortContext; } protected override IEnumerable<TElement> Sort(IEnumerable<TElement> source) { return QuickSort<TElement>.Sort(source, CreateContext(null)); } } }