Imported Upstream version 4.0.0~alpha1

Former-commit-id: 806294f5ded97629b74c85c09952f2a74fe182d9

external/referencesource/mscorlib/system/charenumerator.cs

@@ -0,0 +1,84 @@
+// ==++==
+// 
+//   Copyright (c) Microsoft Corporation.  All rights reserved.
+// 
+// ==--==
+/*============================================================
+**
+** Class: CharEnumerator
+**
+**
+** Purpose: Enumerates the characters on a string.  skips range
+**          checks.
+**
+**
+============================================================*/
+namespace System {
+
+    using System.Collections;
+    using System.Collections.Generic;
+    using System.Diagnostics.Contracts;
+
+[System.Runtime.InteropServices.ComVisible(true)]
+    [Serializable] 
+    public sealed class CharEnumerator : IEnumerator, ICloneable, IEnumerator<char>, IDisposable {
+        private String str;
+        private int index;
+        private char currentElement;
+
+        internal CharEnumerator(String str) {
+            Contract.Requires(str != null);
+            this.str = str;
+            this.index = -1;
+        }
+
+        public Object Clone() {
+            return MemberwiseClone();
+        }
+    
+        public bool MoveNext() {
+            if (index < (str.Length-1)) {
+                index++;
+                currentElement = str[index];
+                return true;
+            }
+            else
+                index = str.Length;
+            return false;
+
+        }
+
+        public void Dispose() {
+            if (str != null)
+                index = str.Length;
+            str = null;
+        }
+    
+        /// <internalonly/>
+        Object IEnumerator.Current {
+            get {
+                if (index == -1)
+                    throw new InvalidOperationException(Environment.GetResourceString(ResId.InvalidOperation_EnumNotStarted));
+                if (index >= str.Length)
+                    throw new InvalidOperationException(Environment.GetResourceString(ResId.InvalidOperation_EnumEnded));                        
+                    
+                return currentElement;
+            }
+        }
+    
+        public char Current {
+            get {
+                if (index == -1)
+                    throw new InvalidOperationException(Environment.GetResourceString(ResId.InvalidOperation_EnumNotStarted));
+                if (index >= str.Length)
+                    throw new InvalidOperationException(Environment.GetResourceString(ResId.InvalidOperation_EnumEnded));                                            
+                return currentElement;
+            }
+        }
+
+        public void Reset() {
+            currentElement = (char)0;
+            index = -1;
+        }
+    }
+}