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43 lines
1.2 KiB
43 lines
1.2 KiB
// 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 |