Tidy.Core.Lexer.FindGivenVersion C# (CSharp) Method

        public virtual HtmlVersion FindGivenVersion(Node doctype)
        {
            int i;

            /* if root tag for doctype isn't html give up now */
            string str1 = GetString(Lexbuf, doctype.Start, 5);
            if (String.CompareOrdinal(str1, "html ") != 0)
            {
                return 0;
            }

            if (!CheckDocTypeKeyWords(doctype))
            {
                Report.Warning(this, doctype, null, Report.DTYPE_NOT_UPPER_CASE);
            }

            /* give up if all we are given is the system id for the doctype */
            str1 = GetString(Lexbuf, doctype.Start + 5, 7);
            if (String.CompareOrdinal(str1, "SYSTEM ") == 0)
            {
                /* but at least ensure the case is correct */
                if (!str1.Substring(0, (6) - (0)).Equals("SYSTEM"))
                {
                    Array.Copy(GetBytes("SYSTEM"), 0, Lexbuf, doctype.Start + 5, 6);
                }
                return 0; /* unrecognized */
            }

            if (String.CompareOrdinal(str1, "PUBLIC ") == 0)
            {
                if (!str1.Substring(0, (6) - (0)).Equals("PUBLIC"))
                    Array.Copy(GetBytes("PUBLIC "), 0, Lexbuf, doctype.Start + 5, 6);
            }
            else
            {
                BadDoctype = true;
            }

            for (i = doctype.Start; i < doctype.End; ++i)
            {
                if (Lexbuf[i] != (byte) '"') continue;
                str1 = GetString(Lexbuf, i + 1, 12);
                string str2 = GetString(Lexbuf, i + 1, 13);
                string p;
                string s;
                int j;
                int len;
                if (str1.Equals("-//W3C//DTD "))
                {
                    /* compute length of identifier e.g. "HTML 4.0 Transitional" */
                    //TODO:odd!
                    for (j = i + 13; j < doctype.End && Lexbuf[j] != (byte) '/'; ++j)
                    {
                    }

                    len = j - i - 13;
                    p = GetString(Lexbuf, i + 13, len);

                    for (j = 1; j < W3CVersion.Length; ++j)
                    {
                        s = W3CVersion[j].Name;
                        if (len == s.Length && s.Equals(p))
                        {
                            return W3CVersion[j].Version;
                        }
                    }

                    /* else unrecognized version */
                }
                else if (str2.Equals("-//IETF//DTD "))
                {
                    /* compute length of identifier e.g. "HTML 2.0" */
                    //TODO:odd!
                    for (j = i + 14; j < doctype.End && Lexbuf[j] != (byte) '/'; ++j)
                    {
                    }

                    len = j - i - 14;

                    p = GetString(Lexbuf, i + 14, len);
                    s = W3CVersion[0].Name;
                    if (len == s.Length && s.Equals(p))
                    {
                        return W3CVersion[0].Version;
                    }

                    /* else unrecognized version */
                }
                break;
            }

            return 0;
        }