WhitespaceReader.cs

Go to the documentation of this file.

using System.Net.Mime;
 
namespace System.Net.Mail;
 
internal static class WhitespaceReader
{
    internal static bool TryReadFwsReverse(string data, int index, out int outIndex, bool throwExceptionIfFail)
    {
        bool flag = false;
        while (index >= 0)
        {
            if (data[index] == '\r' && flag)
            {
                flag = false;
            }
            else
            {
                if (data[index] == '\r' || flag)
                {
                    if (throwExceptionIfFail)
                    {
                        throw new FormatException(System.SR.MailAddressInvalidFormat);
                    }
                    outIndex = 0;
                    return false;
                }
                if (data[index] == '\n')
                {
                    flag = true;
                }
                else if (data[index] != ' ' && data[index] != '\t')
                {
                    break;
                }
            }
            index--;
        }
        if (flag)
        {
            if (throwExceptionIfFail)
            {
                throw new FormatException(System.SR.MailAddressInvalidFormat);
            }
            outIndex = 0;
            return false;
        }
        outIndex = index;
        return true;
    }
 
    internal static bool TryReadCfwsReverse(string data, int index, out int outIndex, bool throwExceptionIfFail)
    {
        int num = 0;
        if (!TryReadFwsReverse(data, index, out index, throwExceptionIfFail))
        {
            outIndex = 0;
            return false;
        }
        while (index >= 0)
        {
            if (!QuotedPairReader.TryCountQuotedChars(data, index, permitUnicodeEscaping: true, out var outIndex2, throwExceptionIfFail))
            {
                outIndex = 0;
                return false;
            }
            if (num > 0 && outIndex2 > 0)
            {
                index -= outIndex2;
            }
            else if (data[index] == ')')
            {
                num++;
                index--;
            }
            else if (data[index] == '(')
            {
                num--;
                if (num < 0)
                {
                    if (throwExceptionIfFail)
                    {
                        throw new FormatException(System.SR.Format(System.SR.MailHeaderFieldInvalidCharacter, '('));
                    }
                    outIndex = 0;
                    return false;
                }
                index--;
            }
            else
            {
                if (num <= 0 || (data[index] <= '\u007f' && !MailBnfHelper.Ctext[(uint)data[index]]))
                {
                    if (num <= 0)
                    {
                        break;
                    }
                    if (throwExceptionIfFail)
                    {
                        throw new FormatException(System.SR.Format(System.SR.MailHeaderFieldInvalidCharacter, data[index]));
                    }
                    outIndex = 0;
                    return false;
                }
                index--;
            }
            if (!TryReadFwsReverse(data, index, out index, throwExceptionIfFail))
            {
                outIndex = 0;
                return false;
            }
        }
        if (num > 0)
        {
            if (throwExceptionIfFail)
            {
                throw new FormatException(System.SR.Format(System.SR.MailHeaderFieldInvalidCharacter, ')'));
            }
            outIndex = 0;
            return false;
        }
        outIndex = index;
        return true;
    }
}