TextElementEnumerator.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / clr / src / BCL / System / Globalization / TextElementEnumerator.cs / 1305376 / TextElementEnumerator.cs
                        
                        
                            // ==++== 
//
//   Copyright (c) Microsoft Corporation.  All rights reserved.
//
// ==--== 
////////////////////////////////////////////////////////////////////////////
// 
//  Class:    TextElementEnumerator 
//
//  Purpose: 
//
//  Date:     [....] 31, 1999
//
//////////////////////////////////////////////////////////////////////////// 

using System.Runtime.Serialization; 
 

namespace System.Globalization { 
    using System.Collections;
    using System.Diagnostics.Contracts;

    // 
    // This is public because GetTextElement() is public.
    // 
 
    [Serializable]
[System.Runtime.InteropServices.ComVisible(true)] 
    public class TextElementEnumerator: IEnumerator
    {
        private String str;
        private int index; 
        private int startIndex;
 
        [NonSerialized] 
        private int strLen;                // This is the length of the total string, counting from the beginning of string.
 
        [NonSerialized]
        private int currTextElementLen; // The current text element lenght after MoveNext() is called.

        [OptionalField(VersionAdded = 2)] 
        private UnicodeCategory uc;
 
        [OptionalField(VersionAdded = 2)] 
        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(); 
        }

#region Serialization
        // the following fields is defined to keep the compatibility with Everett. 
        // don't change/remove the names/types of these fields.
        private int endIndex; 
        private int nextTextElementLen; 

        [OnDeserializing] 
        private void OnDeserializing(StreamingContext ctx)
        {
            charLen = -1;
        } 

        [OnDeserialized] 
        private void OnDeserialized(StreamingContext ctx) 
        {
            strLen              = endIndex + 1; 
            currTextElementLen  = nextTextElementLen;

            if (charLen == -1)
            { 
                uc = CharUnicodeInfo.InternalGetUnicodeCategory(str, index, out charLen);
            } 
        } 

        [OnSerializing] 
        private void OnSerializing(StreamingContext ctx)
        {
            endIndex            = strLen - 1;
            nextTextElementLen  = currTextElementLen; 
        }
 
#endregion Serialization 

 

        [System.Security.SecuritySafeCritical]  // auto-generated
        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(Environment.GetResourceString("InvalidOperation_EnumNotStarted")); 
            } 
            if (index > strLen) {
                throw new InvalidOperationException(Environment.GetResourceString("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(Environment.GetResourceString("InvalidOperation_EnumNotStarted")); 
                }
                return (index - currTextElementLen); 
            }
        }

 
        [System.Security.SecuritySafeCritical]  // auto-generated
        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);
            }
        } 
    }
} 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
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TextElementEnumerator.cs source code in C# .NET

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