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43 lines
1.2 KiB
43 lines
1.2 KiB
5 years ago
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// Copyright (c) Microsoft. All rights reserved.
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// Licensed under the MIT license. See LICENSE file in the project root for full license information.
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#if !NET_4_6
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using System.Collections.Generic;
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namespace System.Dynamic.Utils
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{
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// Miscellaneous helpers that don't belong anywhere else
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internal static class Helpers
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{
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internal static T CommonNode<T>(T first, T second, Func<T, T> parent) where T : class
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{
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// NOTICE this method has no null check
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var cmp = EqualityComparer<T>.Default;
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if (cmp.Equals(first, second))
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{
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return first;
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}
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var set = new HashSet<T>(cmp);
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for (var t = first; t != null; t = parent(t))
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{
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set.Add(t);
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}
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for (var t = second; t != null; t = parent(t))
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{
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if (set.Contains(t))
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{
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return t;
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}
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}
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return null;
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}
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internal static void IncrementCount<T>(T key, Dictionary<T, int> dict)
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{
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int count;
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dict.TryGetValue(key, out count);
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dict[key] = count + 1;
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}
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}
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}
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#endif
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