mcs/class/System.Core/System.Linq/OrderedSequence.cs

   1 //
   2 // OrderedSequence.cs
   3 //
   4 // Authors:
   5 //      Alejandro Serrano "Serras" (trupill@yahoo.es)
   6 //      Marek Safar  <marek.safar@gmail.com>
   7 //      Jb Evain  <jbevain@novell.com>
   8 //
   9 // Copyright (C) 2007 Novell, Inc (http://www.novell.com)
  10 //
  11 // Permission is hereby granted, free of charge, to any person obtaining
  12 // a copy of this software and associated documentation files (the
  13 // "Software"), to deal in the Software without restriction, including
  14 // without limitation the rights to use, copy, modify, merge, publish,
  15 // distribute, sublicense, and/or sell copies of the Software, and to
  16 // permit persons to whom the Software is furnished to do so, subject to
  17 // the following conditions:
  18 //
  19 // The above copyright notice and this permission notice shall be
  20 // included in all copies or substantial portions of the Software.
  21 //
  22 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  23 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  24 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  25 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  26 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  27 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  28 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  29 //
  30
  31 using System;
  32 using System.Collections;
  33 using System.Collections.Generic;
  34
  35 namespace System.Linq {
  36
  37         class OrderedSequence<TElement, TKey> : OrderedEnumerable<TElement> {
  38
  39                 OrderedEnumerable<TElement> parent;
  40
  41                 Func<TElement, TKey> selector;
  42                 IComparer<TKey> comparer;
  43                 SortDirection direction;
  44
  45                 internal OrderedSequence (IEnumerable<TElement> source, Func<TElement, TKey> key_selector, IComparer<TKey> comparer, SortDirection direction)
  46                         : base (source)
  47                 {
  48                         this.selector = key_selector;
  49                         this.comparer = comparer ?? Comparer<TKey>.Default;
  50                         this.direction = direction;
  51                 }
  52
  53                 internal OrderedSequence (OrderedEnumerable<TElement> parent, IEnumerable<TElement> source, Func<TElement, TKey> keySelector, IComparer<TKey> comparer, SortDirection direction)
  54                         : this (source, keySelector, comparer, direction)
  55                 {
  56                         this.parent = parent;
  57                 }
  58
  59                 public override SortContext<TElement> CreateContext (SortContext<TElement> current)
  60                 {
  61                         SortContext<TElement> context = new SortSequenceContext<TElement, TKey> (selector, comparer, direction, current);
  62
  63                         if (parent != null)
  64                                 return parent.CreateContext (context);
  65
  66                         return context;
  67                 }
  68
  69                 protected override IEnumerable<TElement> Sort (IEnumerable<TElement> source)
  70                 {
  71                         return QuickSort<TElement>.Sort (source, CreateContext (null));
  72                 }
  73         }
  74 }