202E; RIGHT-TO-LEFT OVERRIDE
   206A; INHIBIT SYMMETRIC SWAPPING
   206B; ACTIVATE SYMMETRIC SWAPPING
   206C; INHIBIT ARABIC FORM SHAPING
   206D; ACTIVATE ARABIC FORM SHAPING
   206E; NATIONAL DIGIT SHAPES

      return null;
    }
    int digit = AsciiDigits.digit(string.charAt(index++));
    if (digit < 0 || digit >= radix) {
      return null;
    }
    long accum = -digit;

    long cap = Long.MIN_VALUE / radix;

    while (index < string.length()) {
      digit = AsciiDigits.digit(string.charAt(index++));
      if (digit < 0 || digit >= radix || accum < cap) {
        return null;
      }

      int digit = Character.digit(string.charAt(pos), radix);
      if (digit == -1) {
        throw new NumberFormatException(string);
      }
      if (pos > maxSafePos && ParseOverflowDetection.overflowInParse(value, digit, radix)) {
        throw new NumberFormatException("Too large for unsigned long: " + string);
      }
      value = (value * radix) + digit;
    }

    return value;
  }

1F106         ; disallowed_STD3_mapped ; 0035 002C     # 5.2  DIGIT FIVE COMMA
1F107         ; disallowed_STD3_mapped ; 0036 002C     # 5.2  DIGIT SIX COMMA
1F108         ; disallowed_STD3_mapped ; 0037 002C     # 5.2  DIGIT SEVEN COMMA
1F109         ; disallowed_STD3_mapped ; 0038 002C     # 5.2  DIGIT EIGHT COMMA
1F10A         ; disallowed_STD3_mapped ; 0039 002C     # 5.2  DIGIT NINE COMMA

    return Digit.INSTANCE;
  }

  /**
   * Determines whether a character is a BMP digit according to {@linkplain Character#isDigit(char)
   * Java's definition}. If you only care to match ASCII digits, you can use {@code inRange('0',
   * '9')}.
   *
   * @deprecated Many digits are supplementary characters; see the class documentation.
   * @since 19.0 (since 1.0 as constant {@code JAVA_DIGIT})
   */
  @Deprecated

    assertThat(stringPrep("\u200e")).isNull() // LEFT-TO-RIGHT MARK
    assertThat(stringPrep("\u206e")).isNull() // NATIONAL DIGIT SHAPES
    assertThat(stringPrep("\u206f")).isNull() // NOMINAL DIGIT SHAPES
  }

  @Test fun prohibitionTaggingCharacters() {
    assertThat(stringPrep("\udb40\udc01")).isNull() // Note that this is one code point.

//
// ```
// <quantity>        ::= <signedNumber><suffix>
//
// 	(Note that <suffix> may be empty, from the "" case in <decimalSI>.)
//
// <digit>           ::= 0 | 1 | ... | 9
// <digits>          ::= <digit> | <digit><digits>
// <number>          ::= <digits> | <digits>.<digits> | <digits>. | .<digits>
// <sign>            ::= "+" | "-"
// <signedNumber>    ::= <number> | <sign><number>

    return Digit.INSTANCE;
  }

  /**
   * Determines whether a character is a BMP digit according to {@linkplain Character#isDigit(char)
   * Java's definition}. If you only care to match ASCII digits, you can use {@code inRange('0',
   * '9')}.
   *
   * @deprecated Many digits are supplementary characters; see the class documentation.
   * @since 19.0 (since 1.0 as constant {@code JAVA_DIGIT})
   */
  @Deprecated

        if (pos == limit) return false // Malformed.
        val c = string[pos++]
        val digit =
          when (c) {
            in 'a'..'z' -> c - 'a'
            in 'A'..'Z' -> c - 'A'
            in '0'..'9' -> c - '0' + 26
            else -> return false // Malformed.
          }
        val deltaI = digit * w
        if (i > Int.MAX_VALUE - deltaI) return false // Prevent overflow.
        i += deltaI

      throw new NumberFormatException();
    }
    int octet = 0;
    for (int i = start; i < end; i++) {
      octet *= 10;
      int digit = Character.digit(ipString.charAt(i), 10);
      if (digit < 0) {
        throw new NumberFormatException();
      }
      octet += digit;
    }
    if (octet > 255) {
      throw new NumberFormatException();
    }
    return (byte) octet;
  }