From 52229c1472e565bec34b1a6995286a8566dc4928 Mon Sep 17 00:00:00 2001
From: Chris Cameron <chris.cameron@icdsystems.com>
Date: Sun, 29 Sep 2019 21:56:19 -0400
Subject: [PATCH] feat: Adding AreOrdered enumerable extension methods

---
 CHANGELOG.md                                  |  1 +
 .../Extensions/EnumerableExtensionsTest.cs    |  9 ++++
 .../Extensions/EnumerableExtensions.cs        | 44 +++++++++++++++++++
 3 files changed, 54 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index f8f548c..18acc97 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 
 ### Added
  - IcdEnvironment.GetUtcTime() to get UTC representaiton of current time.
+ - Extension methods for determining if a sequence is in order
 
 ## [9.9.0] - 2019-09-16
 ### Added
diff --git a/ICD.Common.Utils.Tests/Extensions/EnumerableExtensionsTest.cs b/ICD.Common.Utils.Tests/Extensions/EnumerableExtensionsTest.cs
index 2de5281..dbe4261 100644
--- a/ICD.Common.Utils.Tests/Extensions/EnumerableExtensionsTest.cs
+++ b/ICD.Common.Utils.Tests/Extensions/EnumerableExtensionsTest.cs
@@ -284,6 +284,15 @@ namespace ICD.Common.Utils.Tests.Extensions
 			Assert.AreEqual(5, items.Length);
 		}
 
+		[TestCase(true)]
+		[TestCase(true, 1, 2, 3, 4)]
+		[TestCase(true, 1, 2, 2, 3, 4)]
+		[TestCase(false, 4, 3, 2, 1)]
+		public void AreOrderedTest(bool expected, params int[] items)
+		{
+			Assert.AreEqual(expected, items.AreOrdered());
+		}
+
 		[Test]
 		public void OrderTest()
 		{
diff --git a/ICD.Common.Utils/Extensions/EnumerableExtensions.cs b/ICD.Common.Utils/Extensions/EnumerableExtensions.cs
index 6c977cb..ada0f46 100644
--- a/ICD.Common.Utils/Extensions/EnumerableExtensions.cs
+++ b/ICD.Common.Utils/Extensions/EnumerableExtensions.cs
@@ -648,6 +648,50 @@ namespace ICD.Common.Utils.Extensions
 				yield return default(T);
 		}
 
+		/// <summary>
+		/// Returns true if the given sequence is ordered.
+		/// </summary>
+		/// <typeparam name="T"></typeparam>
+		/// <param name="extends"></param>
+		/// <returns></returns>
+		public static bool AreOrdered<T>(this IEnumerable<T> extends)
+		{
+			if (extends == null)
+				throw new ArgumentNullException("extends");
+
+			return extends.AreOrdered(Comparer<T>.Default);
+		}
+
+		/// <summary>
+		/// Returns true if the given sequence is ordered.
+		/// </summary>
+		/// <typeparam name="T"></typeparam>
+		/// <param name="extends"></param>
+		/// <param name="comparer"></param>
+		/// <returns></returns>
+		public static bool AreOrdered<T>(this IEnumerable<T> extends, IComparer<T> comparer)
+		{
+			if (extends == null)
+				throw new ArgumentNullException("extends");
+
+			if (comparer == null)
+				throw new ArgumentNullException("comparer");
+
+			bool first = true;
+			T previous = default(T);
+
+			foreach (T item in extends)
+			{
+				if (!first && comparer.Compare(item, previous) < 0)
+					return false;
+
+				first = false;
+				previous = item;
+			}
+
+			return true;
+		}
+
 		/// <summary>
 		/// Default ordering for the items in the sequence.
 		/// </summary>