TextElementEnumerator.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / DotNET / DotNET / 8.0 / untmp / whidbey / REDBITS / ndp / clr / src / BCL / System / Globalization / TextElementEnumerator.cs / 1 / TextElementEnumerator.cs
                        

                        
                            // ==++== 
//
//   Copyright (c) Microsoft Corporation.  All rights reserved.
//
// ==--== 
////////////////////////////////////////////////////////////////////////////
// 
//  Class:    TextElementEnumerator 
//
//  Purpose: 
//
//  Date:     March 31, 1999
//
//////////////////////////////////////////////////////////////////////////// 

using System.Runtime.Serialization; 
 

namespace System.Globalization { 
    using System.Collections;

    //
    // 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) 
        {
            BCLDebug.Assert(str != null, "TextElementEnumerator(): str != null");
            BCLDebug.Assert(startIndex >= 0 && strLen >= 0, "TextElementEnumerator(): startIndex >= 0 && strLen >= 0");
            BCLDebug.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 
 

 
        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); 
            }
        } 


        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);
            } 
        }
    }
}

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