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SIP Stack with SIP Proxy - (VOIP)

, 11 Jun 2007
C# implementation of SIP
SIP_Proxy_demo.zip
SIP_Proxy_demo
SIP_Proxy_demo.suo
SIP_Proxy_demo
bin
Debug
LumiSoft.Net.dll
SIP_Proxy_demo.exe
SIP_Proxy_demo.vshost.exe
dep
LumiSoft.Net.dll
LumiSoft.Net.pdb
Properties
Settings.settings
Resources
add.ico
app.ico
delete.ico
edit.ico
error.ico
info.ico
refresh.ico
rule.ico
server_running.ico
server_stopped.ico
viewmessages.ico
Stack.zip
Net
docs
dns
dns_records.jpg
dns_records.vsd
Net
_junk
_Obsolete
AUTH
bin
Release
LumiSoft.Net.dll
Data
Dns
Client
FTP
Client
Server
HTTP
Server
ICMP
IMAP
Client
Server
IO
Log
LumiSoft.Net
Mime
vCard
Net.csproj.user
Net.suo
NNTP
Client
POP3
Client
Server
RTP
SDP
ServersCore
SIP
Client
Message
Proxy
Stack
SMTP
Client
Server
STUN
Client
Message
URI
using System;
using System.Collections;
using System.Collections.Generic;
using System.Text;

namespace LumiSoft.Net
{
	/// <summary>
	/// This class provides usefull text methods.
	/// </summary>
	public class TextUtils
	{      
		#region static method QuoteString

		/// <summary>
        /// Qoutes and escapes fishy(\") chars.
        /// </summary>
        /// <param name="text">Text to quote.</param>
        /// <returns></returns>
        public static string QuoteString(string text)
        {
            StringBuilder retVal = new StringBuilder();

            for(int i=0;i<text.Length;i++){
                char c = text[i];

                if(c == '\\'){
                    retVal.Append("\\\\");
                }
                else if(c == '\"'){
                    retVal.Append("\\\"");
                }
                else{
                    retVal.Append(c);
                }
            }

            return "\"" + retVal.ToString() + "\"";
        }

		#endregion
         
        #region static method UnQuoteString

        /// <summary>
        /// Unquotes and unescapes escaped chars specified text. For example "xxx" will become to 'xxx', "escaped quote \"", will become to escaped 'quote "'.
        /// </summary>
        /// <param name="text">Text to unquote.</param>
        /// <returns></returns>
        public static string UnQuoteString(string text)
        {
            int startPosInText = 0;
            int endPosInText   = text.Length;
           
            //--- Trim. We can't use standard string.Trim(), it's slow. ----//
            for(int i=0;i<endPosInText;i++){
                char c = text[i];
                if(c == ' ' || c == '\t'){
                    startPosInText++;
                }
                else{
                    break;
                }
            }
            for(int i=endPosInText-1;i>0;i--){
                char c = text[i];
                if(c == ' ' || c == '\t'){
                    endPosInText--;
                }
                else{
                    break;
                }
            }
            //--------------------------------------------------------------//
         
            // All text trimmed
            if((endPosInText - startPosInText) <= 0){
                return "";
            }

            // Remove starting and ending quotes.         
            if(text[startPosInText] == '\"'){
				startPosInText++;
			}
			if(text[endPosInText - 1] == '\"'){
				endPosInText--;
			}

            char[] chars = new char[endPosInText - startPosInText];
            
            int posInChars = 0;
            bool charIsEscaped = false;
            for(int i=startPosInText;i<endPosInText;i++){
                char c = text[i];

                // Escaping char
                if(!charIsEscaped && c == '\\'){
                    charIsEscaped = true;
                }
                // Escaped char
                else if(charIsEscaped){
                    // TODO: replace \n,\r,\t,\v ???
                    chars[posInChars] = c;
                    posInChars++;
                    charIsEscaped = false;
                }
                // Normal char
                else{
                    chars[posInChars] = c;
                    posInChars++;
                    charIsEscaped = false;
                }
            }

            return new string(chars,0,posInChars);
        }

        #endregion

        #region static method EscapeString

        /// <summary>
        /// Escapes specified chars in the specified string.
        /// </summary>
        /// <param name="text">Text to escape.</param>
        /// <param name="charsToEscape">Chars to escape.</param>
		public static string EscapeString(string text,char[] charsToEscape)
        {
            // Create worst scenario buffer, assume all chars must be escaped
            char[] buffer = new char[text.Length * 2];
            int nChars = 0;
            foreach(char c in text){
                foreach(char escapeChar in charsToEscape){
                    if(c == escapeChar){
                        buffer[nChars] = '\\';
                        nChars++;
                        break;
                    }
                }

                buffer[nChars] = c;
                nChars++;
            }

            return new string(buffer,0,nChars);
        }

        #endregion

        #region static method UnEscapeString

        /// <summary>
        /// Unescapes all escaped chars.
        /// </summary>
        /// <param name="text">Text to unescape.</param>
        /// <returns></returns>
        public static string UnEscapeString(string text)
        {
            // Create worst scenarion buffer, non of the chars escaped.
            char[] buffer = new char[text.Length];
            int nChars = 0;
            bool escapedCahr = false;
            foreach(char c in text){
                if(!escapedCahr && c == '\\'){
                    escapedCahr = true;
                }
                else{
                    buffer[nChars] = c;
                    nChars++;
                    escapedCahr = false;
                }                
            }

            return new string(buffer,0,nChars);
        }

        #endregion


		#region static method SplitQuotedString

        /// <summary>
		/// Splits string into string arrays. This split method won't split qouted strings, but only text outside of qouted string.
		/// For example: '"text1, text2",text3' will be 2 parts: "text1, text2" and text3.
		/// </summary>
		/// <param name="text">Text to split.</param>
		/// <param name="splitChar">Char that splits text.</param>
		/// <returns></returns>
		public static string[] SplitQuotedString(string text,char splitChar)
		{
            return SplitQuotedString(text,splitChar,false);
        }

		/// <summary>
		/// Splits string into string arrays. This split method won't split qouted strings, but only text outside of qouted string.
		/// For example: '"text1, text2",text3' will be 2 parts: "text1, text2" and text3.
		/// </summary>
		/// <param name="text">Text to split.</param>
		/// <param name="splitChar">Char that splits text.</param>
		/// <param name="unquote">If true, splitted parst will be unqouted if they are qouted.</param>
		/// <returns></returns>
		public static string[] SplitQuotedString(string text,char splitChar,bool unquote)
		{
			List<string>  splitParts         = new List<string>();  // Holds splitted parts
            int           startPos           = 0;
			bool          inQuotedString     = false;               // Holds flag if position is quoted string or not
            char          lastChar           = '0';

            for(int i=0;i<text.Length;i++){
			    char c = text[i];

                // Start/end quoted string area. Ingonre escaped \".
                if(lastChar != '\\' && c == '\"'){					
					inQuotedString = !inQuotedString;
				}
			
				// Current char is split char and it isn't in quoted string, do split
				if(!inQuotedString && c == splitChar){
					// Add current currentSplitBuffer value to splitted parts list
                    if(unquote){
					    splitParts.Add(UnQuoteString(text.Substring(startPos,i - startPos)));
                    }
                    else{                        
                        splitParts.Add(text.Substring(startPos,i - startPos));
                    }

                    // Store new split part start position.
                    startPos = i + 1;
				}
                lastChar = c;
			}
			// Add last split part to splitted parts list
            if(unquote){
			    splitParts.Add(UnQuoteString(text.Substring(startPos,text.Length - startPos)));
            }
            else{
                splitParts.Add(text.Substring(startPos,text.Length - startPos));
            }

			return splitParts.ToArray();
		}

		#endregion


		#region method QuotedIndexOf

		/// <summary>
		/// Gets first index of specified char. The specified char in quoted string is skipped.
		/// Returns -1 if specified char doesn't exist.
		/// </summary>
		/// <param name="text">Text in what to check.</param>
		/// <param name="indexChar">Char what index to get.</param>
		/// <returns></returns>
		public static int QuotedIndexOf(string text,char indexChar)
		{
			int  retVal         = -1;
			bool inQuotedString = false; // Holds flag if position is quoted string or not			
			for(int i=0;i<text.Length;i++){
				char c = text[i];

				if(c == '\"'){
					// Start/end quoted string area
					inQuotedString = !inQuotedString;
				}

				// Current char is what index we want and it isn't in quoted string, return it's index
				if(!inQuotedString && c == indexChar){
					return i;
				}
			}

			return retVal;
		}

		#endregion


		#region static method SplitString

		/// <summary>
		/// Splits string into string arrays.
		/// </summary>
		/// <param name="text">Text to split.</param>
		/// <param name="splitChar">Char Char that splits text.</param>
		/// <returns></returns>
		public static string[] SplitString(string text,char splitChar)
		{
			ArrayList splitParts = new ArrayList();  // Holds splitted parts

			int lastSplitPoint = 0;
			int textLength     = text.Length;
			for(int i=0;i<textLength;i++){
				if(text[i] == splitChar){
					// Add current currentSplitBuffer value to splitted parts list
					splitParts.Add(text.Substring(lastSplitPoint,i - lastSplitPoint));

					lastSplitPoint = i + 1;
				}
			}
			// Add last split part to splitted parts list
			if(lastSplitPoint <= textLength){
				splitParts.Add(text.Substring(lastSplitPoint));
			}

			string[] retVal = new string[splitParts.Count];
			splitParts.CopyTo(retVal,0);

			return retVal;
		}

		#endregion


        #region static method IsToken

        /// <summary>
        /// Gets if specified string is valid "token" value.
        /// </summary>
        /// <param name="value">String value to check.</param>
        /// <returns>Returns true if specified string value is valid "token" value.</returns>
        /// <exception cref="ArgumentNullException">Is raised if <b>value</b> is null.</exception>
        public static bool IsToken(string value)
        {
            if(value == null){
                throw new ArgumentNullException(value);
            }

            /* This syntax is taken from rfc 3261, but token must be universal so ... .
                token    =  1*(alphanum / "-" / "." / "!" / "%" / "*" / "_" / "+" / "`" / "'" / "~" )
                alphanum = ALPHA / DIGIT
                ALPHA    =  %x41-5A / %x61-7A   ; A-Z / a-z
                DIGIT    =  %x30-39             ; 0-9
            */

            char[] tokenChars = new char[]{'-','.','!','%','*','_','+','`','\'','~'};
            foreach(char c in value){
                // We don't have letter or digit, so we only may have token char.
                if(!((c >= 0x41 && c <= 0x5A) || (c >= 0x61 && c <= 0x7A) || (c >= 0x30 && c <= 0x39))){
                    bool validTokenChar = false;
                    foreach(char tokenChar in tokenChars){
                        if(c == tokenChar){
                            validTokenChar = true;
                            break;
                        }
                    }
                    if(!validTokenChar){
                        return false;
                    }
                }
            }

            return true;
        }

        #endregion
    }
}

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This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

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About the Author

Ivar Lumi

Estonia Estonia
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Web04 | 2.8.140916.1 | Last Updated 11 Jun 2007
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