}

  /** A byte source that reads chars from this source and encodes them as bytes using a charset. */
  private final class AsByteSource extends ByteSource {

    final Charset charset;

    AsByteSource(Charset charset) {
      this.charset = checkNotNull(charset);
    }

    @Override
    public CharSource asCharSource(Charset charset) {
      if (charset.equals(this.charset)) {

  }

  /** A byte source that reads chars from this source and encodes them as bytes using a charset. */
  private final class AsByteSource extends ByteSource {

    final Charset charset;

    AsByteSource(Charset charset) {
      this.charset = checkNotNull(charset);
    }

    @Override
    public CharSource asCharSource(Charset charset) {
      if (charset.equals(this.charset)) {

      chars.add(randomAlpha());
    }
    for (int i = 0; i < nonAlpha; i++) {
      chars.add(randomNonAlpha());
    }
    Collections.shuffle(chars, random);
    char[] array = Chars.toArray(chars);
    this.testString = new String(array);
  }

  private char randomAlpha() {
    return ALPHA.charAt(random.nextInt(ALPHA.length()));
  }

  private char randomNonAlpha() {

      chars.add(randomAlpha());
    }
    for (int i = 0; i < nonAlpha; i++) {
      chars.add(randomNonAlpha());
    }
    Collections.shuffle(chars, random);
    char[] array = Chars.toArray(chars);
    this.testString = new String(array);
  }

  private char randomAlpha() {
    return ALPHA.charAt(random.nextInt(ALPHA.length()));
  }

  private char randomNonAlpha() {

  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

    Set<Character> positive = Sets.newHashSetWithExpectedSize(chars.length);
    for (char c : chars) {
      positive.add(c);
    }
    for (int c = 0; c <= Character.MAX_VALUE; c++) {
      assertFalse(positive.contains(Character.valueOf((char) c)) ^ m.matches((char) c));
    }
  }

  static char[] randomChars(Random rand, int size) {
    Set<Character> chars = new HashSet<>(size);

    Set<Character> positive = Sets.newHashSetWithExpectedSize(chars.length);
    for (char c : chars) {
      positive.add(c);
    }
    for (int c = 0; c <= Character.MAX_VALUE; c++) {
      assertFalse(positive.contains(Character.valueOf((char) c)) ^ m.matches((char) c));
    }
  }

  static char[] randomChars(Random rand, int size) {
    Set<Character> chars = new HashSet<>(size);

      HashFunction hashFunction, Random random) {
    int size = random.nextInt(8) + 1;
    char[] chars = new char[size];
    for (int i = 0; i < chars.length; i++) {
      chars[i] = random.nextBoolean() ? randomLowSurrogate(random) : randomHighSurrogate(random);
    }
    String string = new String(chars);
    assertEquals(
        hashFunction.hashUnencodedChars(string),

    }

    /**
     * Convert char array to byte array (UTF-8)
     */
    private byte[] charsToBytes(char[] chars) {
        if (chars == null) {
            return null;
        }

        // Use UTF-8 encoding
        byte[] bytes = new byte[chars.length * 3]; // Max 3 bytes per char in UTF-8
        int byteIndex = 0;

        for (char c : chars) {
            if (c < 0x80) {

   *
   * @return the replacement characters, or {@code null} if no escaping was required
   */
  @Override
  protected final char @Nullable [] escape(int cp) {
    if (cp < replacementsLength) {
      char[] chars = replacements[cp];
      if (chars != null) {
        return chars;
      }
    }
    if (cp >= safeMin && cp <= safeMax) {
      return null;
    }
    return escapeUnsafe(cp);
  }