QuotedStringFormatReader.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / Net / System / Net / Mail / QuotedStringFormatReader.cs / 1305376 / QuotedStringFormatReader.cs
                        
                        
                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
//----------------------------------------------------------------------------- 

namespace System.Net.Mail 
{ 
    using System;
    using System.Diagnostics; 
    using System.Net.Mime;

    // RFC 2822 Section 3.2.5 - Quoted strings
    // When a string of characters does not conform to an atom string (Section 3.2.4), it must be enclosed in double 
    // quotes.  This allows for white spaces, quoted/escaped characters, etc.  ("Say hello. \"hello!\" ")
    // 
    // For robustness, we allow the bounding double quotes to be omitted when we have another clear delineator such as 
    // a comma: (abc@x.com, billy bob bob@bob.com), where the display name 'billy bob' should have been quoted.
    // 
    // Quoted strings are allowed as MailAddress components local-part and display-name.
    // e.g. "display name" <"user name"@domain>
    internal static class QuotedStringFormatReader
    { 
        //
        // This method reads a standard quoted string. Departing from the RFC, Unicode is permitted for display-name. 
        // 
        // Preconditions:
        //  - Index must be within the bounds of the data string. 
        //  - The char at the given index is the initial quote. (data[index] == Quote)
        //
        // Return value: The next index past the terminating-quote (data[index + 1] == Quote).
        //   e.g. In (bob "user name"@domain), starting at index=14 (") returns index=3 (space). 
        //
        // A FormatException will be thrown if: 
        // - A non-escaped character is encountered that is not valid in a quoted string. 
        // - A Unicode character is encountered and Unicode has not been allowed.
        // - The final double quote is not found. 
        //
        internal static int ReadReverseQuoted(string data, int index, bool permitUnicode)
        {
            Debug.Assert(0 <= index && index < data.Length, "Index out of range: " + index + ", " + data.Length); 
            // Check for the first bounding quote
            Debug.Assert(data[index] == MailBnfHelper.Quote, "Initial char at index " + index + " was not a quote."); 
 
            // Skip the bounding quote
            index--; 

            do
            {
                // Check for valid whitespace 
                index = WhitespaceReader.ReadFwsReverse(data, index);
                if (index < 0) 
                { 
                    break;
                } 

                // Check for escaped characters
                int quotedCharCount = QuotedPairReader.CountQuotedChars(data, index, permitUnicode);
                if (quotedCharCount > 0) 
                {
                    // Skip quoted pairs 
                    index = index - quotedCharCount; 
                }
                // Check for the terminating quote 
                else if (data[index] == MailBnfHelper.Quote)
                {
                    // Skip the final bounding quote
                    return index - 1; 
                }
                // Check invalid characters 
                else if (!IsValidQtext(permitUnicode, data[index])) 
                {
                    throw new FormatException(SR.GetString(SR.MailHeaderFieldInvalidCharacter, data[index])); 
                }
                // Valid char
                else
                { 
                    index--;
                } 
            } 
            while (index >= 0);
 
            // We started with a quote, but did not end with one
            throw new FormatException(SR.GetString(SR.MailHeaderFieldInvalidCharacter, MailBnfHelper.Quote));
        }
 
        //
        // This method attempts reading quoted-string formatted data when the bounding quotes were omitted. 
        // This is common for e-mail display-names. 
        //
        // Precondition: The index must be within the bounds of the data string. 
        //
        // Return value:
        // - The index of the special delimiter provided.
        //   e.g. In (abc@x.com, billy box bob@bob.com), starting at index=19 (x) returns index=9 (,). 
        // - -1 if the terminating character was not found.
        //   e.g. In (my name username@domain), starting at index=5 (e) returns index=-1. 
        // 
        // A FormatException will be thrown if:
        // - A non-escaped character is encountered that is not valid in a quoted string.  This includes double quotes. 
        // - A Unicode character is encountered and Unicode has not been allowed.
        //
        internal static int ReadReverseUnQuoted(string data, int index, bool permitUnicode, bool expectCommaDelimiter)
        { 
            Debug.Assert(0 <= index && index < data.Length, "Index out of range: " + index + ", " + data.Length);
 
            do 
            {
                // Check for valid whitespace 
                index = WhitespaceReader.ReadFwsReverse(data, index);
                if (index < 0)
                {
                    break; 
                }
                // Check for escaped characters 
                int quotedCharCount = QuotedPairReader.CountQuotedChars(data, index, permitUnicode); 
                if (quotedCharCount > 0)
                { 
                    index = index - quotedCharCount;
                }
                // Check for the terminating char
                else if (expectCommaDelimiter && data[index] == MailBnfHelper.Comma) 
                {
                    break; 
                } 
                // Check invalid characters
                else if (!IsValidQtext(permitUnicode, data[index])) 
                {
                    throw new FormatException(SR.GetString(SR.MailHeaderFieldInvalidCharacter, data[index]));
                }
                // Valid char 
                else
                { 
                    index--; 
                }
            } 
            while (index >= 0);

            return index;
        } 

        // Checks for Unicode characters and characters not allowed in quoted-strings. A quoted string may contain 
        // non-whitespace control characters as well as all remaining ASCII chars except backslash and double quote. 
        private static bool IsValidQtext(bool allowUnicode, char ch)
        { 
            if (ch > MailBnfHelper.Ascii7bitMaxValue)
            {
                return allowUnicode;
            } 
            else
            { 
                return MailBnfHelper.Qtext[ch]; 
            }
        } 
    }
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
Link Menu

Network programming in C#, Network Programming in VB.NET, Network Programming in .NET
This book is available now!
Buy at Amazon US or
Buy at Amazon UK
QuotedStringFormatReader.cs source code in C# .NET

Source code for the .NET framework in C#

Code:

Link Menu
