1 files changed, 123 insertions, 0 deletions
diff --git a/src/mscorlib/corefx/System/Globalization/TextElementEnumerator.cs b/src/mscorlib/corefx/System/Globalization/TextElementEnumerator.cs
new file mode 100644
index 0000000000..f547e3e813
--- /dev/null
+++ b/src/mscorlib/corefx/System/Globalization/TextElementEnumerator.cs
@@ -0,0 +1,123 @@
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+// 
+
+// 
+
+////////////////////////////////////////////////////////////////////////////
+//
+//  Class:    TextElementEnumerator
+//
+//  Purpose:  
+//
+//  Date:     March 31, 1999
+//
+////////////////////////////////////////////////////////////////////////////
+
+using System.Collections;
+using System.Diagnostics.Contracts;
+
+namespace System.Globalization
+{
+    //
+    // This is public because GetTextElement() is public.
+    //
+
+    [System.Runtime.InteropServices.ComVisible(true)]
+    public class TextElementEnumerator : IEnumerator
+    {
+        private String str;
+        private int index;
+        private int startIndex;
+
+        private int strLen;                // This is the length of the total string, counting from the beginning of string.
+
+        private int currTextElementLen; // The current text element lenght after MoveNext() is called.
+
+        private UnicodeCategory uc;
+
+        private int charLen;            // The next abstract char to look at after MoveNext() is called.  It could be 1 or 2, depending on if it is a surrogate or not.
+
+        internal TextElementEnumerator(String str, int startIndex, int strLen)
+        {
+            Contract.Assert(str != null, "TextElementEnumerator(): str != null");
+            Contract.Assert(startIndex >= 0 && strLen >= 0, "TextElementEnumerator(): startIndex >= 0 && strLen >= 0");
+            Contract.Assert(strLen >= startIndex, "TextElementEnumerator(): strLen >= startIndex");
+            this.str = str;
+            this.startIndex = startIndex;
+            this.strLen = strLen;
+            Reset();
+        }
+
+        public bool MoveNext()
+        {
+            if (index >= strLen)
+            {
+                // Make the index to be greater than strLen so that we can throw exception if GetTextElement() is called.
+                index = strLen + 1;
+                return (false);
+            }
+            currTextElementLen = StringInfo.GetCurrentTextElementLen(str, index, strLen, ref uc, ref charLen);
+            index += currTextElementLen;
+            return (true);
+        }
+
+        //
+        // Get the current text element.
+        //
+
+        public Object Current
+        {
+            get
+            {
+                return (GetTextElement());
+            }
+        }
+
+        //
+        // Get the current text element.
+        //
+
+        public String GetTextElement()
+        {
+            if (index == startIndex)
+            {
+                throw new InvalidOperationException(SR.InvalidOperation_EnumNotStarted);
+            }
+            if (index > strLen)
+            {
+                throw new InvalidOperationException(SR.InvalidOperation_EnumEnded);
+            }
+
+            return (str.Substring(index - currTextElementLen, currTextElementLen));
+        }
+
+        //
+        // Get the starting index of the current text element.
+        //
+
+        public int ElementIndex
+        {
+            get
+            {
+                if (index == startIndex)
+                {
+                    throw new InvalidOperationException(SR.InvalidOperation_EnumNotStarted);
+                }
+                return (index - currTextElementLen);
+            }
+        }
+
+
+        public void Reset()
+        {
+            index = startIndex;
+            if (index < strLen)
+            {
+                // If we have more than 1 character, get the category of the current char.
+                uc = CharUnicodeInfo.InternalGetUnicodeCategory(str, index, out charLen);
+            }
+        }
+    }
+}