101 lines
3.1 KiB
C#
101 lines
3.1 KiB
C#
//
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// Lookup<TKey, TElement>.cs
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//
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// Authors:
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// Alejandro Serrano "Serras" (trupill@yahoo.es)
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// Marek Safar <marek.safar@gmail.com>
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// Jb Evain <jbevain@novell.com>
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// Eric Maupin <me@ermau.com>
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//
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// Copyright (C) 2007 Novell, Inc (http://www.novell.com)
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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.Linq {
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public class Lookup<TKey, TElement> : IEnumerable<IGrouping<TKey, TElement>>, ILookup<TKey, TElement> {
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IGrouping<TKey, TElement> nullGrouping;
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Dictionary<TKey, IGrouping<TKey, TElement>> groups;
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public int Count {
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get { return (nullGrouping == null) ? groups.Count : groups.Count + 1; }
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}
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public IEnumerable<TElement> this [TKey key] {
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get {
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if (key == null && nullGrouping != null)
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return nullGrouping;
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else if (key != null) {
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IGrouping<TKey, TElement> group;
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if (groups.TryGetValue (key, out group))
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return group;
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}
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return new TElement [0];
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}
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}
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internal Lookup (Dictionary<TKey, List<TElement>> lookup, IEnumerable<TElement> nullKeyElements)
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{
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groups = new Dictionary<TKey, IGrouping<TKey, TElement>> (lookup.Comparer);
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foreach (var slot in lookup)
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groups.Add (slot.Key, new Grouping<TKey, TElement> (slot.Key, slot.Value));
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if (nullKeyElements != null)
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nullGrouping = new Grouping<TKey, TElement> (default (TKey), nullKeyElements);
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}
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public IEnumerable<TResult> ApplyResultSelector<TResult> (Func<TKey, IEnumerable<TElement>, TResult> resultSelector)
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{
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if (nullGrouping != null)
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yield return resultSelector (nullGrouping.Key, nullGrouping);
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foreach (var group in groups.Values)
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yield return resultSelector (group.Key, group);
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}
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public bool Contains (TKey key)
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{
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return (key != null) ? groups.ContainsKey (key) : nullGrouping != null;
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}
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public IEnumerator<IGrouping<TKey, TElement>> GetEnumerator ()
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{
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if (nullGrouping != null)
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yield return nullGrouping;
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foreach (var g in groups.Values)
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yield return g;
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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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