internal static bool IsProhibited()

in MySQL.Data/src/Authentication/MySqlSASLPlugin.cs [135:203]
52 lines of code
71 McCabe index (conditional complexity)

    internal static bool IsProhibited(string s, int index)
    {
      int u = char.ConvertToUtf32(s, index);

      // Non-ASCII control characters: https://tools.ietf.org/html/rfc3454#appendix-C.2.2
      if ((u >= 0x0080 && u <= 0x009F) || u == 0x06DD || u == 0x070F || u == 0x180E || u == 0x200C || u == 0x200D ||
        u == 0x2028 || u == 0x2029 || (u >= 0x2060 && u <= 0x2063) || (u >= 0x206A && u <= 0x206F) || u == 0xFEFF ||
        (u >= 0xFFF9 && u <= 0xFFFC) || (u >= 0x1D173 && u <= 0x1D17A))
        return true;

      // Private Use characters: http://tools.ietf.org/html/rfc3454#appendix-C.3
      if ((u >= 0xE000 && u <= 0xF8FF) || (u >= 0xF0000 && u <= 0xFFFFD) || (u >= 0x100000 && u <= 0x10FFFD))
        return true;

      // Non-character code points: http://tools.ietf.org/html/rfc3454#appendix-C.4
      if ((u >= 0xFDD0 && u <= 0xFDEF) || (u >= 0xFFFE && u <= 0xFFFF) || (u >= 0x1FFFE && u <= 0x1FFFF) ||
        (u >= 0x2FFFE && u <= 0x2FFFF) || (u >= 0x3FFFE && u <= 0x3FFFF) || (u >= 0x4FFFE && u <= 0x4FFFF) ||
        (u >= 0x5FFFE && u <= 0x5FFFF) || (u >= 0x6FFFE && u <= 0x6FFFF) || (u >= 0x7FFFE && u <= 0x7FFFF) ||
        (u >= 0x8FFFE && u <= 0x8FFFF) || (u >= 0x9FFFE && u <= 0x9FFFF) || (u >= 0xAFFFE && u <= 0xAFFFF) ||
        (u >= 0xBFFFE && u <= 0xBFFFF) || (u >= 0xCFFFE && u <= 0xCFFFF) || (u >= 0xDFFFE && u <= 0xDFFFF) ||
        (u >= 0xEFFFE && u <= 0xEFFFF) || (u >= 0xFFFFE && u <= 0xFFFFF) || (u >= 0x10FFFE && u <= 0x10FFFF))
        return true;

      // Surrogate code points: http://tools.ietf.org/html/rfc3454#appendix-C.5
      if (char.IsSurrogate(s, index))
        return true;

      // Inappropriate for plain text: http://tools.ietf.org/html/rfc3454#appendix-C.6
      switch (u)
      {
        case 0xFFF9: // INTERLINEAR ANNOTATION ANCHOR
        case 0xFFFA: // INTERLINEAR ANNOTATION SEPARATOR
        case 0xFFFB: // INTERLINEAR ANNOTATION TERMINATOR
        case 0xFFFC: // OBJECT REPLACEMENT CHARACTER
        case 0xFFFD: // REPLACEMENT CHARACTER
          return true;
      }

      // Inappropriate for canonical representation: http://tools.ietf.org/html/rfc3454#appendix-C.7
      if (u >= 0x2FF0 && u <= 0x2FFB)
        return true;

      // Change display properties or are deprecated: http://tools.ietf.org/html/rfc3454#appendix-C.8
      switch (u)
      {
        case 0x0340: // COMBINING GRAVE TONE MARK
        case 0x0341: // COMBINING ACUTE TONE MARK
        case 0x200E: // LEFT-TO-RIGHT MARK
        case 0x200F: // RIGHT-TO-LEFT MARK
        case 0x202A: // LEFT-TO-RIGHT EMBEDDING
        case 0x202B: // RIGHT-TO-LEFT EMBEDDING
        case 0x202C: // POP DIRECTIONAL FORMATTING
        case 0x202D: // LEFT-TO-RIGHT OVERRIDE
        case 0x202E: // RIGHT-TO-LEFT OVERRIDE
        case 0x206A: // INHIBIT SYMMETRIC SWAPPING
        case 0x206B: // ACTIVATE SYMMETRIC SWAPPING
        case 0x206C: // INHIBIT ARABIC FORM SHAPING
        case 0x206D: // ACTIVATE ARABIC FORM SHAPING
        case 0x206E: // NATIONAL DIGIT SHAPES
        case 0x206F: // NOMINAL DIGIT SHAPES
          return true;
      }

      // Tagging characters: http://tools.ietf.org/html/rfc3454#appendix-C.9
      if (u == 0xE0001 || (u >= 0xE0020 && u <= 0xE007F))
        return true;

      return false;
    }