Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

mcs/class/referencesource/System.Activities/System/Activities/Validation/ExtensionMethods.cs

@@ -0,0 +1,126 @@
+//-----------------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+//-----------------------------------------------------------------------------
+
+namespace System.Activities.Validation
+{
+    using System.Collections;
+    using System.Collections.Generic;
+    using System.Text;
+
+    static class ExtensionMethods
+    {
+        public static bool IsNullOrEmpty(this ICollection c)
+        {
+            return (c == null || c.Count == 0);
+        }
+
+        public static string AsCommaSeparatedValues(this IEnumerable<string> c)
+        {
+            StringBuilder sb = new StringBuilder();
+            foreach (string s in c)
+            {
+                if (!string.IsNullOrEmpty(s))
+                {
+                    if (sb.Length == 0)
+                    {
+                        sb.Append(s);
+                    }
+                    else
+                    {
+                        sb.Append(", ");
+                        sb.Append(s);
+                    }
+                }
+            }
+            return sb.ToString();
+        }
+
+        public static int BinarySearch<T>(this IList<T> items, T value, IComparer<T> comparer)
+        {
+            return BinarySearch(items, 0, items.Count, value, comparer);
+        }
+
+        public static void QuickSort<T>(this IList<T> items, IComparer<T> comparer)
+        {
+            QuickSort(items, 0, items.Count - 1, comparer);
+        }
+
+        static int BinarySearch<T>(IList<T> items, int startIndex, int length, T value, IComparer<T> comparer)
+        {
+            int start = startIndex;
+            int end = (startIndex + length) - 1;
+            while (start <= end)
+            {
+                int mid = start + ((end - start) >> 1);
+                int result = comparer.Compare(items[mid], value);
+                if (result == 0)
+                {
+                    return mid;
+                }
+                if (result < 0)
+                {
+                    start = mid + 1;
+                }
+                else
+                {
+                    end = mid - 1;
+                }
+            }
+            return ~start;
+        }
+
+        static void QuickSort<T>(IList<T> items, int startIndex, int endIndex, IComparer<T> comparer)
+        {
+            Stack<int> bounds = new Stack<int>();
+            do
+            {
+                if (bounds.Count != 0)
+                {
+                    endIndex = bounds.Pop();
+                    startIndex = bounds.Pop();
+                }
+
+                T pivot = items[startIndex];
+                int pivotIndex = startIndex;
+
+                for (int i = startIndex + 1; i <= endIndex; i++)
+                {
+                    if (comparer.Compare(pivot, items[i]) > 0)
+                    {
+                        pivotIndex++;
+                        if (pivotIndex != i)
+                        {
+                            items.Swap(pivotIndex, i);
+                        }
+                    }
+                }
+
+                if (startIndex != pivotIndex)
+                {
+                    items.Swap(startIndex, pivotIndex);
+                }
+
+                if (pivotIndex + 1 < endIndex)
+                {
+                    bounds.Push(pivotIndex + 1); 
+                    bounds.Push(endIndex);
+                }
+
+                if (startIndex < pivotIndex - 1)
+                {
+                    bounds.Push(startIndex); 
+                    bounds.Push(pivotIndex - 1);
+                }
+
+            } while (bounds.Count != 0);
+        }
+
+        static void Swap<T>(this IList<T> items, int i, int j)
+        {
+            T temp = items[i];
+            items[i] = items[j];
+            items[j] = temp;
+        }
+    }
+}