using System.Collections.Generic; namespace System.Linq { internal class SortSequenceContext<TElement, TKey> : SortContext<TElement> { private Func<TElement, TKey> selector; private IComparer<TKey> comparer; private TKey[] keys; public SortSequenceContext(Func<TElement, TKey> selector, IComparer<TKey> comparer, SortDirection direction, SortContext<TElement> child_context) : base(direction, child_context) { this.selector = selector; this.comparer = comparer; } public override void Initialize(TElement[] elements) { if (child_context != null) child_context.Initialize(elements); keys = new TKey[elements.Length]; for (int i = 0; i < keys.Length; i++) { keys[i] = selector(elements[i]); } } public override int Compare(int first_index, int second_index) { int num = comparer.Compare(keys[first_index], keys[second_index]); if (num == 0) { if (child_context != null) return child_context.Compare(first_index, second_index); num = ((direction == SortDirection.Descending) ? (second_index - first_index) : (first_index - second_index)); } if (direction != SortDirection.Descending) return num; return -num; } } }