DomainLiteralReader.cs

Go to the documentation of this file.

using System.Net.Mime;
 
namespace System.Net.Mail;
 
internal static class DomainLiteralReader
{
    internal static bool TryReadReverse(string data, int index, out int outIndex, bool throwExceptionIfFail)
    {
        index--;
        do
        {
            if (!WhitespaceReader.TryReadFwsReverse(data, index, out index, throwExceptionIfFail))
            {
                outIndex = 0;
                return false;
            }
            if (index < 0)
            {
                break;
            }
            if (!QuotedPairReader.TryCountQuotedChars(data, index, permitUnicodeEscaping: false, out var outIndex2, throwExceptionIfFail))
            {
                outIndex = 0;
                return false;
            }
            if (outIndex2 > 0)
            {
                index -= outIndex2;
                continue;
            }
            if (data[index] == '[')
            {
                outIndex = index - 1;
                return true;
            }
            if (data[index] > '\u007f' || !MailBnfHelper.Dtext[(uint)data[index]])
            {
                if (throwExceptionIfFail)
                {
                    throw new FormatException(System.SR.Format(System.SR.MailHeaderFieldInvalidCharacter, data[index]));
                }
                outIndex = 0;
                return false;
            }
            index--;
        }
        while (index >= 0);
        if (throwExceptionIfFail)
        {
            throw new FormatException(System.SR.Format(System.SR.MailHeaderFieldInvalidCharacter, ']'));
        }
        outIndex = 0;
        return false;
    }
}