private static final class AnyOf extends CharMatcher {

    private final char[] chars;

    AnyOf(CharSequence chars) {
      this.chars = chars.toString().toCharArray();
      Arrays.sort(this.chars);
    }

    @Override
    public boolean matches(char c) {
      return Arrays.binarySearch(chars, c) >= 0;
    }

    @Override

    if (chars instanceof String) {
      return toLowerCase((String) chars);
    }
    char[] newChars = new char[chars.length()];
    for (int i = 0; i < newChars.length; i++) {
      newChars[i] = toLowerCase(chars.charAt(i));
    }
    return String.valueOf(newChars);
  }

  /**
   * If the argument is an {@linkplain #isUpperCase(char) uppercase ASCII character}, returns the

          private final char[] unknown = new char[] {'?'};

          @Override
          protected char[] escapeUnsafe(char c) {
            return unknown;
          }
        };
    EscaperAsserts.assertBasic(replacingEscaper);

    // Replacements are applied first regardless of whether the character is in
    // the safe range or not ('&' is a safe char while '\t' and '\n' are not).

  }

  static CharMatcher from(BitSet chars, String description) {
    // Compute the filter.
    long filter = 0;
    int size = chars.cardinality();
    boolean containsZero = chars.get(0);
    // Compute the hash table.
    char[] table = new char[chooseTableSize(size)];
    int mask = table.length - 1;
    for (int c = chars.nextSetBit(0); c != -1; c = chars.nextSetBit(c + 1)) {

      }
    }
  }

  private static String mikeRepeat(String string, int count) {
    int len = string.length();
    char[] strCopy = new char[len * Integer.highestOneBit(count)];
    string.getChars(0, len, strCopy, 0);

    char[] array = new char[len * count];

    int strCopyLen = len;
    int pos = 0;
    while (count != 0) {
      if ((count & 1) != 0) {

    }

    @Test
    @DisplayName("Should convert hex chars correctly")
    void testToHexChars() {
        // Test integer conversion
        char[] dst1 = new char[8];
        Hexdump.toHexChars(0x1234ABCD, dst1, 0, 8);
        assertEquals("1234ABCD", new String(dst1));

        // Test with smaller size
        char[] dst2 = new char[4];
        Hexdump.toHexChars(0xABCD, dst2, 0, 4);

        Arrays.fill(decrypted, '\0');
    }

    @Test
    public void testEncryptDecryptEmpty() throws Exception {
        char[] plaintext = new char[0];

        byte[] encrypted = storage.encryptCredentials(plaintext);
        assertNotNull(encrypted, "Encrypted empty data should not be null");

        char[] decrypted = storage.decryptCredentials(encrypted);
        assertNotNull(decrypted, "Decrypted empty data should not be null");

      while (i + 4 <= utf16Length) {
        char c0 = input.charAt(i);
        char c1 = input.charAt(i + 1);
        char c2 = input.charAt(i + 2);
        char c3 = input.charAt(i + 3);
        if (c0 < 0x80 && c1 < 0x80 && c2 < 0x80 && c3 < 0x80) {
          int k1 = c0 | (c1 << 8) | (c2 << 16) | (c3 << 24);
          k1 = mixK1(k1);
          h1 = mixH1(h1, k1);
          i += 4;

            return "";
        }
        final int mod = inData.length % 3;
        final int num = inData.length / 3;
        char[] outData = null;
        if (mod != 0) {
            outData = new char[(num + 1) * 4];
        } else {
            outData = new char[num * 4];
        }
        for (int i = 0; i < num; i++) {
            encode(inData, i * 3, outData, i * 4);
        }
        if (mod == 1) {

   */
  @Override
  protected final char @Nullable [] escape(char c) {
    if (c < replacementsLength) {
      char[] chars = replacements[c];
      if (chars != null) {
        return chars;
      }
    }
    if (c >= safeMin && c <= safeMax) {
      return null;
    }
    return escapeUnsafe(c);
  }

  /**