Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

mcs/class/referencesource/System.Activities/System/Activities/Debugger/BinarySearchResult.cs

@@ -0,0 +1,80 @@
+// <copyright>
+//   Copyright (c) Microsoft Corporation.  All rights reserved.
+// </copyright>
+
+namespace System.Activities.Debugger
+{
+    using System.Diagnostics;
+    using System.Diagnostics.CodeAnalysis;
+
+    [DebuggerDisplay("{this.ToString()}")]
+    internal class BinarySearchResult
+    {
+        private int result;
+        private int count;
+
+        internal BinarySearchResult(int resultFromBinarySearch, int count)
+        {
+            this.result = resultFromBinarySearch;
+            this.count = count;
+        }
+
+        internal bool IsFound
+        {
+            get { return this.result >= 0; }
+        }
+
+        [DebuggerBrowsable(DebuggerBrowsableState.Never)]
+        internal int FoundIndex
+        {
+            get
+            {
+                UnitTestUtility.Assert(this.IsFound, "We should not call FoundIndex if we cannot find the element.");
+                return this.result;
+            }
+        }
+
+        [DebuggerBrowsable(DebuggerBrowsableState.Never)]
+        internal int NextIndex
+        {
+            get
+            {
+                UnitTestUtility.Assert(!this.IsFound, "We should not call NextIndex if we found the element.");
+                UnitTestUtility.Assert(this.IsNextIndexAvailable, "We should not call NextIndex if next index is not available.");
+                return this.NextIndexValue;
+            }
+        }
+
+        [DebuggerBrowsable(DebuggerBrowsableState.Never)]
+        internal bool IsNextIndexAvailable
+        {
+            get
+            {
+                UnitTestUtility.Assert(!this.IsFound, "We should not call IsNextIndexAvailable if we found the element.");
+                return this.NextIndexValue != this.count;
+            }
+        }
+
+        private int NextIndexValue
+        {
+            get { return ~this.result; }
+        }
+
+        [SuppressMessage("Microsoft.Globalization", "CA1305:SpecifyIFormatProvider", MessageId = "System.String.Format(System.String,System.Object)", Justification = "Message used in debugger only.")]
+        public override string ToString()
+        {
+            if (this.IsFound)
+            {
+                return string.Format("Data is found at index {0}.", this.FoundIndex);
+            }
+            else if (this.IsNextIndexAvailable)
+            {
+                return string.Format("Data is not found, the next index is {0}.", this.NextIndex);
+            }
+            else
+            {
+                return "Data is not found and there is no next index.";
+            }
+        }
+    }
+}