From 482424a714c129e8ecd9cc8f780dededa0414816 Mon Sep 17 00:00:00 2001
From: Chris Cameron <chris.cameron@wedoresi.com>
Date: Mon, 12 Feb 2018 14:32:36 -0500
Subject: [PATCH] Adding extension method for finding distinct items in a
 sequence based on a callback

---
 .../Extensions/EnumerableExtensions.cs        | 20 +++++++++++
 ICD.Common.Utils/FuncComparer.cs              | 33 +++++++++++++++++++
 .../ICD.Common.Utils_SimplSharp.csproj        |  1 +
 3 files changed, 54 insertions(+)
 create mode 100644 ICD.Common.Utils/FuncComparer.cs

diff --git a/ICD.Common.Utils/Extensions/EnumerableExtensions.cs b/ICD.Common.Utils/Extensions/EnumerableExtensions.cs
index d28fe0a..d8c0ae1 100644
--- a/ICD.Common.Utils/Extensions/EnumerableExtensions.cs
+++ b/ICD.Common.Utils/Extensions/EnumerableExtensions.cs
@@ -643,6 +643,7 @@ namespace ICD.Common.Utils.Extensions
 		/// <typeparam name="TValue"></typeparam>
 		/// <param name="extends"></param>
 		/// <returns></returns>
+		[PublicAPI]
 		public static Dictionary<TKey, TValue> ToDictionary<TKey, TValue>(this IEnumerable<KeyValuePair<TKey, TValue>> extends)
 		{
 			if (extends == null)
@@ -651,6 +652,25 @@ namespace ICD.Common.Utils.Extensions
 			return extends.ToDictionary(x => x.Key, x => x.Value);
 		}
 
+		/// <summary>
+		/// Shim to
+		/// </summary>
+		/// <typeparam name="T"></typeparam>
+		/// <param name="extends"></param>
+		/// <param name="comparer"></param>
+		/// <returns></returns>
+		[PublicAPI]
+		public static IEnumerable<T> Distinct<T>(this IEnumerable<T> extends, Func<T, T, bool> comparer)
+		{
+			if (extends == null)
+				throw new ArgumentNullException("extends");
+
+			if (comparer == null)
+				throw new ArgumentNullException("comparer");
+
+			return extends.Distinct(new FuncComparer<T>(comparer));
+		}
+
 		/// <summary>
 		/// Returns other if the sequence is empty.
 		/// Returns other if the sequence is non-empty and there are two different elements.
diff --git a/ICD.Common.Utils/FuncComparer.cs b/ICD.Common.Utils/FuncComparer.cs
new file mode 100644
index 0000000..c9bb76a
--- /dev/null
+++ b/ICD.Common.Utils/FuncComparer.cs
@@ -0,0 +1,33 @@
+using System;
+using System.Collections.Generic;
+
+namespace ICD.Common.Utils
+{
+	/// <summary>
+	/// Simple comparer for comparing items using a callback.
+	/// </summary>
+	/// <typeparam name="T"></typeparam>
+	public sealed class FuncComparer<T> : IEqualityComparer<T>
+	{
+		private readonly Func<T, T, bool> m_Comparer;
+
+		/// <summary>
+		/// Constructor.
+		/// </summary>
+		/// <param name="comparer"></param>
+		public FuncComparer(Func<T, T, bool> comparer)
+		{
+			m_Comparer = comparer;
+		}
+
+		public bool Equals(T x, T y)
+		{
+			return m_Comparer(x, y);
+		}
+
+		public int GetHashCode(T obj)
+		{
+			return obj.GetHashCode();
+		}
+	}
+}
diff --git a/ICD.Common.Utils/ICD.Common.Utils_SimplSharp.csproj b/ICD.Common.Utils/ICD.Common.Utils_SimplSharp.csproj
index e6a5e80..966b40e 100644
--- a/ICD.Common.Utils/ICD.Common.Utils_SimplSharp.csproj
+++ b/ICD.Common.Utils/ICD.Common.Utils_SimplSharp.csproj
@@ -87,6 +87,7 @@
     <None Include="ObfuscationSettings.cs" />
     <Compile Include="Extensions\ByteExtensions.cs" />
     <Compile Include="Extensions\ListExtensions.cs" />
+    <Compile Include="FuncComparer.cs" />
     <Compile Include="ProcessorUtils.SimplSharp.cs" />
     <Compile Include="ProcessorUtils.Standard.cs" />
     <Compile Include="ProgramUtils.SimplSharp.cs" />