* without modification.
   *
   * @since 14.0
   */
  public static String toUpperCase(CharSequence chars) {
    if (chars instanceof String) {
      return toUpperCase((String) chars);
    }
    char[] newChars = new char[chars.length()];
    for (int i = 0; i < newChars.length; i++) {
      newChars[i] = toUpperCase(chars.charAt(i));
    }
    return String.valueOf(newChars);
  }

  /**

   * without modification.
   *
   * @since 14.0
   */
  public static String toUpperCase(CharSequence chars) {
    if (chars instanceof String) {
      return toUpperCase((String) chars);
    }
    char[] newChars = new char[chars.length()];
    for (int i = 0; i < newChars.length; i++) {
      newChars[i] = toUpperCase(chars.charAt(i));
    }
    return String.valueOf(newChars);
  }

  /**

      BaseEncoding encoding, String decoded, String encoded) {
    testEncodingWithSeparators(encoding, decoded, encoded);
    testEncodingWithSeparators(encoding.upperCase(), decoded, Ascii.toUpperCase(encoded));
    testEncodingWithSeparators(encoding.lowerCase(), decoded, Ascii.toLowerCase(encoded));
  }

  private static void testEncodingWithSeparators(

   * <p>Consider normalizing your string references with {@link #nullToEmpty}. If you do, you can
   * use {@link String#isEmpty()} instead of this method, and you won't need special null-safe forms
   * of methods like {@link String#toUpperCase} either. Or, if you'd like to normalize "in the other
   * direction," converting empty strings to {@code null}, you can use {@link #emptyToNull}.
   *
   * @param string a string reference to check

      BaseEncoding encoding, String decoded, String encoded) {
    testEncodingWithSeparators(encoding, decoded, encoded);
    testEncodingWithSeparators(encoding.upperCase(), decoded, Ascii.toUpperCase(encoded));
    testEncodingWithSeparators(encoding.lowerCase(), decoded, Ascii.toLowerCase(encoded));
  }

  private static void testEncodingWithSeparators(

  }

  public void testFromStringFailsWithUpperCaseString() {
    String string = Hashing.sha1().hashString("foo", Charsets.US_ASCII).toString().toUpperCase();
    assertThrows(IllegalArgumentException.class, () -> HashCode.fromString(string));
  }

  public void testFromStringFailsWithShortInputs() {

   * <p>Consider normalizing your string references with {@link #nullToEmpty}. If you do, you can
   * use {@link String#isEmpty()} instead of this method, and you won't need special null-safe forms
   * of methods like {@link String#toUpperCase} either. Or, if you'd like to normalize "in the other
   * direction," converting empty strings to {@code null}, you can use {@link #emptyToNull}.
   *
   * @param string a string reference to check

  }

  public void testFromStringFailsWithUpperCaseString() {
    String string = Hashing.sha1().hashString("foo", Charsets.US_ASCII).toString().toUpperCase();
    assertThrows(IllegalArgumentException.class, () -> HashCode.fromString(string));
  }

  public void testFromStringFailsWithShortInputs() {

      for (Object o : elements) {
        @SuppressWarnings("unchecked")
        Entry<String, String> entry = (Entry<String, String>) o;
        multimap.put(entry.getKey(), Ascii.toUpperCase(entry.getValue()));
      }
      return transform(multimap);
    }

    abstract M transform(Multimap<String, String> multimap);

    @SuppressWarnings("unchecked")
    @Override

      }
      checkState(!hasUpperCase(), "Cannot call upperCase() on a mixed-case alphabet");
      char[] upperCased = new char[chars.length];
      for (int i = 0; i < chars.length; i++) {
        upperCased[i] = Ascii.toUpperCase(chars[i]);
      }
      Alphabet upperCase = new Alphabet(name + ".upperCase()", upperCased);
      return ignoreCase ? upperCase.ignoreCase() : upperCase;
    }

    Alphabet lowerCase() {