129 lines
3.6 KiB
C#
129 lines
3.6 KiB
C#
//
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// OrderedEnumerableRowCollection.cs
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//
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// Author:
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// Atsushi Enomoto <atsushi@ximian.com>
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//
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// Copyright (C) 2008 Novell, Inc. http://www.novell.com
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//
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//
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// Permission is hereby granted, free of charge, to any person obtaining
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// a copy of this software and associated documentation files (the
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// "Software"), to deal in the Software without restriction, including
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// without limitation the rights to use, copy, modify, merge, publish,
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// distribute, sublicense, and/or sell copies of the Software, and to
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// permit persons to whom the Software is furnished to do so, subject to
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// the following conditions:
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//
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// The above copyright notice and this permission notice shall be
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// included in all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
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// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
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// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
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// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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//
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using System;
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using System.Collections;
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using System.Collections.Generic;
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namespace System.Data
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{
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public sealed class OrderedEnumerableRowCollection<TRow>
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: EnumerableRowCollection<TRow>
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{
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internal static OrderedEnumerableRowCollection<TRow> Create<TRow, TKey> (IEnumerable<TRow> source, Func<TRow, TKey> keySelector, IComparer<TKey> comparer, bool descending)
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{
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var sorter = new SortComparer<TRow> ();
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sorter.AddSort<TKey> (keySelector, comparer, descending);
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return new OrderedEnumerableRowCollection<TRow> (new SortedEnumerable <TRow> (source, sorter));
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}
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internal static OrderedEnumerableRowCollection<TRow> AddSort<TRow, TKey> (OrderedEnumerableRowCollection<TRow> source, Func<TRow, TKey> keySelector, IComparer<TKey> comparer, bool descending)
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{
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source.source.Sorter.AddSort<TKey> (keySelector, comparer, descending);
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return source;
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}
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OrderedEnumerableRowCollection (SortedEnumerable<TRow> source)
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: base (source)
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{
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this.source = source;
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}
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SortedEnumerable<TRow> source;
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}
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class SortComparer<TRow> : IComparer<TRow>
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{
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public SortComparer ()
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{
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}
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List<Comparison<TRow>> comparers = new List<Comparison<TRow>> ();
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public void AddSort (Comparison<TRow> comparer)
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{
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comparers.Add (comparer);
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}
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public void AddSort<TKey> (Func<TRow, TKey> keySelector, IComparer<TKey> comparer, bool descending)
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{
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if (keySelector == null)
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throw new ArgumentNullException ("keySelector");
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if (comparer == null)
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comparer = Comparer<TKey>.Default;
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comparers.Add (delegate (TRow r1, TRow r2) {
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int ret = comparer.Compare (keySelector (r1), keySelector (r2));
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return descending ? -ret : ret;
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});
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}
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public int Compare (TRow r1, TRow r2)
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{
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foreach (var c in comparers) {
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int ret = c (r1, r2);
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if (ret != 0)
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return ret;
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}
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return 0;
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}
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}
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class SortedEnumerable<TRow> : IEnumerable<TRow>
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{
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IEnumerable<TRow> source;
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SortComparer<TRow> sorter;
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public SortedEnumerable (IEnumerable<TRow> source, SortComparer<TRow> sorter)
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{
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this.source = source;
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this.sorter = sorter;
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}
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public SortComparer<TRow> Sorter {
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get { return sorter; }
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}
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public IEnumerator<TRow> GetEnumerator ()
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{
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var list = new List<TRow> ();
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foreach (TRow row in source)
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list.Add (row);
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list.Sort (sorter);
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for (int i = 0, c = list.Count; i < c; i++)
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yield return list [i];
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}
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IEnumerator IEnumerable.GetEnumerator ()
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{
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return GetEnumerator ();
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}
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}
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}
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